Short distance illumination of a spatial light modulator using a curved reflector

ABSTRACT

A display device includes a light source, a spatial light modulator, and an optical assembly. The light source is configured to provide illumination light and the spatial light modulator positioned to receive the illumination light. The optical assembly includes an optical element and a curved reflector that is distinct and separate from the optical element. The curved reflector is disposed relative to the light source so that at least a portion of the illumination light is reflected by the curved reflector toward the optical element, is reflected by the optical element toward the curved reflector, and is transmitted through the curved reflector. A method performed by the display device is also disclosed.

RELATED APPLICATIONS

This application claims the benefit of, and priority to, U.S.Provisional Patent Application Ser. No. 62/900,320, filed Sep. 13, 2019,which is incorporated by reference herein in its entirety. Thisapplication is related to (1) U.S. patent application Ser. No.16/858,331, filed on Apr. 24, 2020, entitled “Short DistanceIllumination of a Spatial Light Modulator Using a Pancake LensAssembly”, (2) U.S. patent application Ser. No. 16/858,341, filed onApr. 24, 2020, entitled “Short Distance Illumination of a Spatial LightModulator Using an Optical Element with an Aperture”, and (3) U.S.patent application Ser. No. 16/858,312, filed on Apr. 24, 2020, entitled“Short Distance Illumination of a Spatial Light Modulator Using a SingleReflector”, all of which are incorporated by reference herein in theirentireties.

TECHNICAL FIELD

This relates generally to display devices, and more specifically toilluminators for use in head-mounted display devices.

BACKGROUND

Head-mounted display devices (also called herein head-mounted displays)are gaining popularity as means for providing visual information to auser. For example, the head-mounted display devices are used for virtualreality and augmented reality operations.

High-resolution displays are desired in head-mounted display devices.Because a display of a head-mounted display device is located adjacentto eyes of a user, if a low resolution display is used, the spacingbetween pixels of the display would be visible to the user (as if theview is seen through a screen door). However, high-resolution displaysare large and heavy, which have limited their application inhead-mounted display devices.

SUMMARY

Accordingly, there is a need for compact and light-weighted head-mounteddisplay devices. Such head-mounted display devices will enhance userexperience with virtual reality and/or augmented reality operations.

The above deficiencies and other problems associated with conventionalhead-mounted displays are reduced or eliminated by the disclosed opticalcomponents and display devices.

In accordance with some embodiments, a display device includes a lightsource, a spatial light modulator, and an optical assembly. The lightsource is configured to provide illumination light, and the spatiallight modulator is positioned to receive the illumination light. Theoptical assembly includes a first reflective surface and a secondreflective surface that is opposite to the first reflective surface. Theoptical assembly is positioned relative to the light source so that atleast a first portion of the illumination light received by the opticalassembly is (i) transmitted through the first reflective surface towardthe second reflective surface, (ii) reflected by the second reflectivesurface toward the first reflective surface, (iii) reflected by thefirst reflective surface toward the second reflective surface, and (iv)transmitted through the second reflective surface.

In accordance with some embodiments, a method includes outputtingillumination light from a light source and receiving the illuminationlight at a first reflective surface of an optical assembly. The opticalassembly includes a second reflective surface located opposite to thefirst reflective surface. The method also includes transmitting a firstportion of the illumination light through the first reflective surfacetoward the second reflective surface; and reflecting, at the secondreflective surface, the first portion of the illumination lighttransmitted through the first reflective surface toward the firstreflective surface. The method further includes reflecting, at the firstreflective surface, the first portion of the illumination lightreflected by the second reflective surface toward the second reflectivesurface; and transmitting, through the second reflective surface, thefirst portion of the illumination light reflected by the firstreflective surface. The method also includes receiving the first portionof the illumination light at a spatial light modulator.

In accordance with some embodiments, a display device includes a lightsource, a spatial light modulator, and an optical assembly. The lightsource is configured to provide illumination light and the spatial lightmodulator is positioned to receive the illumination light. The opticalassembly includes a first reflective surface with an aperture and asecond reflective surface that is opposite to the first reflectivesurface. The optical assembly is positioned relative to the light sourceso that at least a first portion of the illumination light received bythe optical assembly is (i) reflected by the second reflective surfacetoward the first reflective surface, (ii) reflected by the firstreflective surface toward the second reflective surface, and (iii)transmitted through the second reflective surface.

In accordance with some embodiments, a method includes outputtingillumination light from a light source. The light source is positionedadjacent to a first reflective surface of an optical assembly. The firstreflective surface defines an aperture and the optical assembly includesa second reflective surface that is located opposite to the firstreflective surface. The method further includes (i) reflecting, at thesecond reflective surface, a first portion of the illumination lighttoward the first reflective surface; (ii) reflecting, at the firstreflective surface, the first portion of the illumination lightreflected by the second reflective surface toward the second reflectivesurface; (iii) transmitting the first portion of the illumination lightreflected by the first reflective surface through the second reflectivesurface; and (iv) receiving the first portion of the illumination lightat a spatial light modulator.

In accordance with some embodiments, a display device includes a lightsource, a spatial light modulator, and an optical assembly. The lightsource is configured to provide illumination light. The spatial lightmodulator is positioned to receive the illumination light. The opticalassembly includes an optical element and a curved reflector that isdistinct and separate from the optical element. The curved reflector isdisposed relative to the light source so that at least a portion of theillumination light is (i) reflected by the curved reflector toward theoptical element, (ii) reflected by the optical element toward the curvedreflector, and (iii) transmitted through the curved reflector.

In accordance with some embodiments, a method includes outputtingillumination light from a light source; receiving the illumination lightat a curved reflector; and reflecting at least a portion of theillumination light at the curved reflector. The method also includesreflecting, at an optical element, the at least a portion of theillumination light reflected by the curved reflector toward the curvedreflector; transmitting, through the curved reflector, the at least aportion of the illumination light reflected by the optical element; andreceiving the at least a portion of the illumination light at a spatiallight modulator.

In accordance with some embodiments, a display device includes a lightsource, a spatial light modulator, and an optical assembly. The lightsource is configured to provide illumination light. The spatial lightmodulator is positioned to receive the illumination light. The opticalelement includes a reflective surface and the optical element ispositioned relative to the light source so that at least a portion ofthe illumination light received by the optical element is reflected atthe reflective surface back toward the light source.

In accordance with some embodiments, a method includes outputtingillumination light from a light source, receiving at least a portion ofthe illumination light at a reflective surface of an optical element,reflecting the at least a portion of the illumination light at thereflective surface, and receiving the at least a portion of theillumination light at a spatial light modulator.

Thus, the disclosed embodiments provide for illuminators and displaydevices that include such illuminators, and methods for using and makingsuch illuminators. In some embodiments, the display devices arehead-mounted display devices.

BRIEF DESCRIPTION OF THE DRAWINGS

For a better understanding of the various described embodiments,reference should be made to the Description of Embodiments below, inconjunction with the following drawings in which like reference numeralsrefer to corresponding parts throughout the figures.

FIG. 1 is a perspective view of a display device in accordance with someembodiments.

FIG. 2 is a block diagram of a system including a display device inaccordance with some embodiments.

FIG. 3A is an isometric view of a display device in accordance with someembodiments.

FIGS. 3B-3C are schematic diagrams illustrating example illuminationconfigurations for use in a display device in accordance with someembodiments.

FIG. 4A is a schematic diagram illustrating a display device inaccordance with some embodiments.

FIGS. 4B-4E illustrate a polarization selective element in accordancewith some embodiments.

FIGS. 4F-4J are schematic diagrams illustrating display devices inaccordance with some embodiments.

FIG. 5A is a schematic diagram illustrating a display device with anoptical assembly in accordance with some embodiments.

FIG. 5B is a schematic diagram illustrating optical paths in the opticalassembly shown in FIG. 5A.

FIGS. 5C-5D are schematic diagrams illustrating display devices inaccordance with some embodiments.

FIGS. 6A-6E are schematic diagrams illustrating display devices inaccordance with some embodiments.

FIG. 7 is a schematic diagram illustrating a display device inaccordance with some embodiments.

FIGS. 8A-8C are schematic diagrams illustrating a light source inaccordance with some embodiments.

FIGS. 9A-9C is a flow diagram illustrating a method of providing shortdistance illumination in accordance with some embodiments.

FIGS. 10A-10C is a flow diagram illustrating a method of providing shortdistance illumination in accordance with some embodiments.

FIGS. 11A-11B is a flow diagram illustrating a method of providing shortdistance illumination in accordance with some embodiments.

FIGS. 12A-12B is a flow diagram illustrating a method of providing shortdistance illumination in accordance with some embodiments.

These figures are not drawn to scale unless indicated otherwise.

DETAILED DESCRIPTION

There is a need for head-mounted display devices that are lightweight,compact, and can provide uniform illumination.

The present disclosure provides display devices that produce uniformillumination in a compact footprint. The display device includes anoptical assembly that is configured to direct illumination light emittedfrom a light source toward a spatial light modulator (e.g., reflectivespatial light modulator).

Reference will now be made to embodiments, examples of which areillustrated in the accompanying drawings. In the following description,numerous specific details are set forth in order to provide anunderstanding of the various described embodiments. However, it will beapparent to one of ordinary skill in the art that the various describedembodiments may be practiced without these specific details. In otherinstances, well-known methods, procedures, components, circuits, andnetworks have not been described in detail so as not to unnecessarilyobscure aspects of the embodiments.

It will also be understood that, although the terms first, second, etc.are, in some instances, used herein to describe various elements, theseelements should not be limited by these terms. These terms are used onlyto distinguish one element from another. For example, a first reflectorcould be termed a second reflector, and, similarly, a second reflectorcould be termed a first reflector, without departing from the scope ofthe various described embodiments. The first reflector and the secondreflector are both light reflectors, but they are not the samereflector.

The terminology used in the description of the various describedembodiments herein is for the purpose of describing particularembodiments only and is not intended to be limiting. As used in thedescription of the various described embodiments and the appendedclaims, the singular forms “a,” “an,” and “the” are intended to includethe plural forms as well, unless the context clearly indicatesotherwise. It will also be understood that the term “and/or” as usedherein refers to and encompasses any and all possible combinations ofone or more of the associated listed items. It will be furtherunderstood that the terms “includes,” “including,” “comprises,” and/or“comprising,” when used in this specification, specify the presence ofstated features, integers, steps, operations, elements, and/orcomponents, but do not preclude the presence or addition of one or moreother features, integers, steps, operations, elements, components,and/or groups thereof. The term “exemplary” is used herein in the senseof “serving as an example, instance, or illustration” and not in thesense of “representing the best of its kind.”

FIG. 1 illustrates display device 100 in accordance with someembodiments. In some embodiments, display device 100 is configured to beworn on a head of a user (e.g., by having the form of spectacles oreyeglasses, as shown in FIG. 1 ) or to be included as part of a helmetthat is to be worn by the user. When display device 100 is configured tobe worn on a head of a user or to be included as part of a helmet,display device 100 is called a head-mounted display. Alternatively,display device 100 is configured for placement in proximity of an eye oreyes of the user at a fixed location, without being head-mounted (e.g.,display device 100 is mounted in a vehicle, such as a car or anairplane, for placement in front of an eye or eyes of the user). Asshown in FIG. 1 , display device 100 includes display 110. Display 110is configured for presenting visual contents (e.g., augmented realitycontents, virtual reality contents, mixed reality contents, or anycombination thereof) to a user.

In some embodiments, display device 100 includes one or more componentsdescribed herein with respect to FIG. 2 . In some embodiments, displaydevice 100 includes additional components not shown in FIG. 2 .

FIG. 2 is a block diagram of system 200 in accordance with someembodiments. The system 200 shown in FIG. 2 includes display device 205(which corresponds to display device 100 shown in FIG. 1 ), imagingdevice 235, and input interface 240 that are each coupled to console210. While FIG. 2 shows an example of system 200 including displaydevice 205, imaging device 235, and input interface 240, in otherembodiments, any number of these components may be included in system200. For example, there may be multiple display devices 205 each havingassociated input interface 240 and being monitored by one or moreimaging devices 235, with each display device 205, input interface 240,and imaging devices 235 communicating with console 210. In alternativeconfigurations, different and/or additional components may be includedin system 200. For example, in some embodiments, console 210 isconnected via a network (e.g., the Internet) to system 200 or isself-contained as part of display device 205 (e.g., physically locatedinside display device 205). In some embodiments, display device 205 isused to create mixed reality by adding in a view of the realsurroundings. Thus, display device 205 and system 200 described here candeliver augmented reality, virtual reality, and mixed reality.

In some embodiments, as shown in FIG. 1 , display device 205 correspondsto display device 100 and is a head-mounted display that presents mediato a user. Examples of media presented by display device 205 include oneor more images, video, audio, or some combination thereof. In someembodiments, audio is presented via an external device (e.g., speakersand/or headphones) that receives audio information from display device205, console 210, or both, and presents audio data based on the audioinformation. In some embodiments, display device 205 immerses a user inan augmented environment.

In some embodiments, display device 205 also acts as an augmentedreality (AR) headset. In these embodiments, display device 205 augmentsviews of a physical, real-world environment with computer-generatedelements (e.g., images, video, sound, etc.). Moreover, in someembodiments, display device 205 is able to cycle between different typesof operation. Thus, display device 205 operate as a virtual reality (VR)device, an augmented reality (AR) device, as glasses or some combinationthereof (e.g., glasses with no optical correction, glasses opticallycorrected for the user, sunglasses, or some combination thereof) basedon instructions from application engine 255.

Display device 205 includes electronic display 215, one or moreprocessors 216, eye tracking module 217, adjustment module 218, one ormore locators 220, one or more position sensors 225, one or moreposition cameras 222, memory 228, inertial measurement unit (IMU) 230,one or more optical assemblies 260, or a subset or superset thereof(e.g., display device 205 with electronic display 215, optical assembly260, without any other listed components). Some embodiments of displaydevice 205 have different modules than those described here. Similarly,the functions can be distributed among the modules in a different mannerthan is described here.

One or more processors 216 (e.g., processing units or cores) executeinstructions stored in memory 228. Memory 228 includes high-speed randomaccess memory, such as DRAM, SRAM, DDR RAM or other random access solidstate memory devices; and may include non-volatile memory, such as oneor more magnetic disk storage devices, optical disk storage devices,flash memory devices, or other non-volatile solid state storage devices.Memory 228, or alternately the non-volatile memory device(s) withinmemory 228, includes a non-transitory computer readable storage medium.In some embodiments, memory 228 or the computer readable storage mediumof memory 228 stores programs, modules and data structures, and/orinstructions for displaying one or more images on electronic display215.

Electronic display 215 displays images to the user in accordance withdata received from console 210 and/or processor(s) 216. In variousembodiments, electronic display 215 may comprise a single adjustabledisplay element or multiple adjustable display elements (e.g., a displayfor each eye of a user). In some embodiments, electronic display 215 isconfigured to project images to the user through one or more opticalassemblies 260.

In some embodiments, the display element includes one or more lightemission devices and a corresponding array of spatial light modulators.A spatial light modulator is an array of electro-optic pixels,opto-electronic pixels, some other array of devices that dynamicallyadjust the amount of light transmitted by each device, or somecombination thereof. These pixels are placed behind one or more lenses.In some embodiments, the spatial light modulator is an array of liquidcrystal based pixels in an LCD (a Liquid Crystal Display). Examples ofthe light emission devices include: an organic light emitting diode, anactive-matrix organic light-emitting diode, a light emitting diode, sometype of device capable of being placed in a flexible display, or somecombination thereof. The light emission devices include devices that arecapable of generating visible light (e.g., red, green, blue, etc.) usedfor image generation. The spatial light modulator is configured toselectively attenuate individual light emission devices, groups of lightemission devices, or some combination thereof. Alternatively, when thelight emission devices are configured to selectively attenuateindividual emission devices and/or groups of light emission devices, thedisplay element includes an array of such light emission devices withouta separate emission intensity array.

One or more optical components in the one or more optical assemblies 260direct light from the arrays of light emission devices (optionallythrough the emission intensity arrays) to locations within each eyeboxand ultimately to the back of the user's retina(s). An eyebox is aregion that is occupied by an eye of a user of display device 205 (e.g.,a user wearing display device 205) who is viewing images from displaydevice 205. In some cases, the eyebox is represented as a 10 mm×10 mmsquare. In some embodiments, the one or more optical components includeone or more coatings, such as anti-reflective coatings, and one or morepolarization volume holograms (PVH).

In some embodiments, the display element includes an infrared (IR)detector array that detects IR light that is retro-reflected from theretinas of a viewing user, from the surface of the corneas, lenses ofthe eyes, or some combination thereof. The IR detector array includes anIR sensor or a plurality of IR sensors that each correspond to adifferent position of a pupil of the viewing user's eye. In alternateembodiments, other eye tracking systems may also be employed.

Eye tracking module 217 determines locations of each pupil of a user'seyes. In some embodiments, eye tracking module 217 instructs electronicdisplay 215 to illuminate the eyebox with IR light (e.g., via IRemission devices in the display element).

A portion of the emitted IR light will pass through the viewing user'spupil and be retro-reflected from the retina toward the IR detectorarray, which is used for determining the location of the pupil.Additionally or alternatively, the reflection off of the surfaces of theeye is used to also determine location of the pupil. In some cases, theIR detector array scans for retro-reflection and identifies which IRemission devices are active when retro-reflection is detected. Eyetracking module 217 may use a tracking lookup table and the identifiedIR emission devices to determine the pupil locations for each eye. Thetracking lookup table maps the received signals on the IR detector arrayto locations (corresponding to pupil locations) in each eyebox. In someembodiments, the tracking lookup table is generated via a calibrationprocedure (e.g., user looks at various known reference points in animage and eye tracking module 217 maps the locations of the user's pupilwhile looking at the reference points to corresponding signals receivedon the IR tracking array). As mentioned above, in some embodiments,system 200 may use other eye tracking systems than the embedded IR eyetracking system described herein.

Adjustment module 218 generates an image frame based on the determinedlocations of the pupils. In some embodiments, this sends a discreteimage to the display that will tile sub-images together thus a coherentstitched image will appear on the back of the retina. Adjustment module218 adjusts an output (i.e. the generated image frame) of electronicdisplay 215 based on the detected locations of the pupils. Adjustmentmodule 218 instructs portions of electronic display 215 to pass imagelight to the determined locations of the pupils. In some embodiments,adjustment module 218 also instructs the electronic display not toprovide image light to positions other than the determined locations ofthe pupils. Adjustment module 218 may, for example, block and/or stoplight emission devices whose image light falls outside of the determinedpupil locations, allow other light emission devices to emit image lightthat falls within the determined pupil locations, translate and/orrotate one or more display elements, dynamically adjust curvature and/orrefractive power of one or more active lenses in the lens (e.g.,microlens) arrays, or some combination thereof.

Optional locators 220 are objects located in specific positions ondisplay device 205 relative to one another and relative to a specificreference point on display device 205. A locator 220 may be a lightemitting diode (LED), a corner cube reflector, a reflective marker, atype of light source that contrasts with an environment in which displaydevice 205 operates, or some combination thereof. In embodiments wherelocators 220 are active (i.e., an LED or other type of light emittingdevice), locators 220 may emit light in the visible band (e.g., about400 nm to 750 nm), in the infrared band (e.g., about 750 nm to 1 mm), inthe ultraviolet band (about 100 nm to 400 nm), some other portion of theelectromagnetic spectrum, or some combination thereof.

In some embodiments, locators 220 are located beneath an outer surfaceof display device 205, which is transparent to the wavelengths of lightemitted or reflected by locators 220 or is thin enough to notsubstantially attenuate the wavelengths of light emitted or reflected bylocators 220. Additionally, in some embodiments, the outer surface orother portions of display device 205 are opaque in the visible band ofwavelengths of light. Thus, locators 220 may emit light in the IR bandunder an outer surface that is transparent in the IR band but opaque inthe visible band.

IMU 230 is an electronic device that generates calibration data based onmeasurement signals received from one or more position sensors 225.Position sensor 225 generates one or more measurement signals inresponse to motion of display device 205. Examples of position sensors225 include: one or more accelerometers, one or more gyroscopes, one ormore magnetometers, another suitable type of sensor that detects motion,a type of sensor used for error correction of IMU 230, or somecombination thereof. Position sensors 225 may be located external to IMU230, internal to IMU 230, or some combination thereof.

Based on the one or more measurement signals from one or more positionsensors 225, IMU 230 generates first calibration data indicating anestimated position of display device 205 relative to an initial positionof display device 205. For example, position sensors 225 includemultiple accelerometers to measure translational motion (forward/back,up/down, left/right) and multiple gyroscopes to measure rotationalmotion (e.g., pitch, yaw, roll). In some embodiments, IMU 230 rapidlysamples the measurement signals and calculates the estimated position ofdisplay device 205 from the sampled data. For example, IMU 230integrates the measurement signals received from the accelerometers overtime to estimate a velocity vector and integrates the velocity vectorover time to determine an estimated position of a reference point ondisplay device 205. Alternatively, IMU 230 provides the sampledmeasurement signals to console 210, which determines the firstcalibration data. The reference point is a point that may be used todescribe the position of display device 205. While the reference pointmay generally be defined as a point in space; however, in practice thereference point is defined as a point within display device 205 (e.g., acenter of IMU 230).

In some embodiments, IMU 230 receives one or more calibration parametersfrom console 210. As further discussed below, the one or morecalibration parameters are used to maintain tracking of display device205. Based on a received calibration parameter, IMU 230 may adjust oneor more IMU parameters (e.g., sample rate). In some embodiments, certaincalibration parameters cause IMU 230 to update an initial position ofthe reference point so it corresponds to a next calibrated position ofthe reference point. Updating the initial position of the referencepoint as the next calibrated position of the reference point helpsreduce accumulated error associated with the determined estimatedposition. The accumulated error, also referred to as drift error, causesthe estimated position of the reference point to “drift” away from theactual position of the reference point over time.

Imaging device 235 generates calibration data in accordance withcalibration parameters received from console 210. Calibration dataincludes one or more images showing observed positions of locators 220that are detectable by imaging device 235. In some embodiments, imagingdevice 235 includes one or more still cameras, one or more videocameras, any other device capable of capturing images including one ormore locators 220, or some combination thereof. Additionally, imagingdevice 235 may include one or more filters (e.g., used to increasesignal to noise ratio). Imaging device 235 is configured to optionallydetect light emitted or reflected from locators 220 in a field of viewof imaging device 235. In embodiments where locators 220 include passiveelements (e.g., a retroreflector), imaging device 235 may include alight source that illuminates some or all of locators 220, whichretro-reflect the light toward the light source in imaging device 235.Second calibration data is communicated from imaging device 235 toconsole 210, and imaging device 235 receives one or more calibrationparameters from console 210 to adjust one or more imaging parameters(e.g., focal length, focus, frame rate, ISO, sensor temperature, shutterspeed, aperture, etc.).

In some embodiments, display device 205 includes one or more opticalassemblies 260. In some embodiments, display device 205 optionallyincludes a single optical assembly 260 or multiple optical assemblies260 (e.g., an optical assembly 260 for each eye of a user). In someembodiments, the one or more optical assemblies 260 receive image lightfor the computer generated images from the electronic display device(s)215 and direct the image light toward an eye or eyes of a user. Thecomputer-generated images include still images, animated images, and/ora combination thereof. The computer-generated images include objectsthat appear to be two-dimensional and/or three-dimensional objects.

In some embodiments, electronic display device 215 projectscomputer-generated images to one or more reflective elements (notshown), and the one or more optical assemblies receive the image lightfrom the one or more reflective elements and direct the image light tothe eye(s) of the user. In some embodiments, the one or more reflectiveelements are partially transparent (e.g., the one or more reflectiveelements have a transmittance of at least 15%, 20%, 25%, 30%, 35%, 40%,45%, or 50%), which allows transmission of ambient light. In suchembodiments, computer-generated images projected by electronic display215 are superimposed with the transmitted ambient light (e.g.,transmitted ambient image) to provide augmented reality images.

Input interface 240 is a device that allows a user to send actionrequests to console 210. An action request is a request to perform aparticular action. For example, an action request may be to start or endan application or to perform a particular action within the application.Input interface 240 may include one or more input devices. Example inputdevices include: a keyboard, a mouse, a game controller, data from brainsignals, data from other parts of the human body, or any other suitabledevice for receiving action requests and communicating the receivedaction requests to console 210. An action request received by inputinterface 240 is communicated to console 210, which performs an actioncorresponding to the action request. In some embodiments, inputinterface 240 may provide haptic feedback to the user in accordance withinstructions received from console 210. For example, haptic feedback isprovided when an action request is received, or console 210 communicatesinstructions to input interface 240 causing input interface 240 togenerate haptic feedback when console 210 performs an action.

Console 210 provides media to display device 205 for presentation to theuser in accordance with information received from one or more of:imaging device 235, display device 205, and input interface 240. In theexample shown in FIG. 2 , console 210 includes application store 245,tracking module 250, and application engine 255. Some embodiments ofconsole 210 have different modules than those described in conjunctionwith FIG. 2 . Similarly, the functions further described herein may bedistributed among components of console 210 in a different manner thanis described here.

When application store 245 is included in console 210, application store245 stores one or more applications for execution by console 210. Anapplication is a group of instructions, that when executed by aprocessor, is used for generating content for presentation to the user.Content generated by the processor based on an application may be inresponse to inputs received from the user via movement of display device205 or input interface 240. Examples of applications include: gamingapplications, conferencing applications, video playback application, orother suitable applications.

When tracking module 250 is included in console 210, tracking module 250calibrates system 200 using one or more calibration parameters and mayadjust one or more calibration parameters to reduce error indetermination of the position of display device 205. For example,tracking module 250 adjusts the focus of imaging device 235 to obtain amore accurate position for observed locators on display device 205.Moreover, calibration performed by tracking module 250 also accounts forinformation received from IMU 230. Additionally, if tracking of displaydevice 205 is lost (e.g., imaging device 235 loses line of sight of atleast a threshold number of locators 220), tracking module 250re-calibrates some or all of system 200.

In some embodiments, tracking module 250 tracks movements of displaydevice 205 using second calibration data from imaging device 235. Forexample, tracking module 250 determines positions of a reference pointof display device 205 using observed locators from the secondcalibration data and a model of display device 205. In some embodiments,tracking module 250 also determines positions of a reference point ofdisplay device 205 using position information from the first calibrationdata. Additionally, in some embodiments, tracking module 250 may useportions of the first calibration data, the second calibration data, orsome combination thereof, to predict a future location of display device205. Tracking module 250 provides the estimated or predicted futureposition of display device 205 to application engine 255.

Application engine 255 executes applications within system 200 andreceives position information, acceleration information, velocityinformation, predicted future positions, or some combination thereof ofdisplay device 205 from tracking module 250. Based on the receivedinformation, application engine 255 determines content to provide todisplay device 205 for presentation to the user. For example, if thereceived information indicates that the user has looked to the left,application engine 255 generates content for display device 205 thatmirrors the user's movement in an augmented environment. Additionally,application engine 255 performs an action within an applicationexecuting on console 210 in response to an action request received frominput interface 240 and provides feedback to the user that the actionwas performed. The provided feedback may be visual or audible feedbackvia display device 205 or haptic feedback via input interface 240.

FIG. 3A is an isometric view of display device 300 in accordance withsome embodiments. In some other embodiments, display device 300 is partof some other electronic display (e.g., a digital microscope, ahead-mounted display device, etc.). In some embodiments, display device300 includes light emission device 310 and an optical assembly 330,which may include one or more lenses and/or other optical components. Insome embodiments, display device 300 also includes an IR detector array.

Light emission device 310 emits image light and optional IR light towardthe viewing user. Light emission device 310 includes one or more lightemission components that emit light in the visible light (and optionallyincludes components that emit light in the IR). Light emission device310 may include, e.g., an array of LEDs, an array of microLEDs, an arrayof OLEDs, or some combination thereof.

In some embodiments, light emission device 310 includes an emissionintensity array (e.g., a spatial light modulator) configured toselectively attenuate light emitted from light emission device 310. Insome embodiments, the emission intensity array is composed of aplurality of liquid crystal cells or pixels, groups of light emissiondevices, or some combination thereof. Each of the liquid crystal cellsis, or in some embodiments, groups of liquid crystal cells are,addressable to have specific levels of attenuation. For example, at agiven time, some of the liquid crystal cells may be set to noattenuation, while other liquid crystal cells may be set to maximumattenuation. In this manner, the emission intensity array is able toprovide image light and/or control what portion of the image light ispassed to the optical assembly 330. In some embodiments, display device300 uses the emission intensity array to facilitate providing imagelight to a location of pupil 350 of eye 340 of a user, and minimize theamount of image light provided to other areas in the eyebox.

The optical assembly 330 includes one or more lenses. The one or morelenses in optical assembly 330 receive modified image light (e.g.,attenuated light) from light emission device 310, and direct themodified image light to a location of pupil 350. The optical assembly330 may include additional optical components, such as color filters,mirrors, etc.

An optional IR detector array detects IR light that has beenretro-reflected from the retina of eye 340, a cornea of eye 340, acrystalline lens of eye 340, or some combination thereof. The IRdetector array includes either a single IR sensor or a plurality of IRsensitive detectors (e.g., photodiodes). In some embodiments, the IRdetector array is separate from light emission device 310. In someembodiments, the IR detector array is integrated into light emissiondevice 310.

In some embodiments, light emission device 310 including an emissionintensity array make up a display element. Alternatively, the displayelement includes light emission device 310 (e.g., when light emissiondevice 310 includes individually adjustable pixels) without the emissionintensity array. In some embodiments, the display element additionallyincludes the IR array. In some embodiments, in response to a determinedlocation of pupil 350, the display element adjusts the emitted imagelight such that the light output by the display element is refracted byone or more lenses toward the determined location of pupil 350, and nottoward other locations in the eyebox.

In some embodiments, display device 300 includes one or more broadbandsources (e.g., one or more white LEDs) coupled with a plurality of colorfilters, in addition to, or instead of, light emission device 310.

In some embodiments, display device 300 (or light emission device 310 ofdisplay device 300) includes a spatial light modulator (e.g., areflective spatial light modulator), such as a Liquid Crystal on Silicon(LCoS) spatial light modulator. In some embodiments, the LCoS spatiallight modulator includes liquid crystals. In some embodiments, the LCoSspatial light modulator includes ferroelectric liquid crystals. Thespatial light modulator has an array of pixels (or subpixels), and arespective pixel (or a respective subpixel) may be individuallycontrolled to reflect light impinging thereon (e.g., a pixel isactivated to reflect light impinging thereon or deactivated to ceasereflecting the light impinging thereon) or modulate the reflected light(e.g., a pixel is activated to change the polarization of the reflectedlight or deactivated to cease changing the polarization of the reflectedlight, or vice versa). In some embodiments, display device 300 includesmultiple spatial light modulators (e.g., a first spatial light modulatorfor a first color, such as red, a second spatial light modulator for asecond color, such as green, and a third spatial light modulator for athird color, such as blue). Such a spatial light modulator requires anilluminator that provides light to the spatial light modulator.

LCoS spatial light modulators typically reflect a portion ofillumination light to provide image light, and non-uniformity in theillumination light will lead to non-uniformity in the image light. Thus,there is a need for compact illuminators that can provide uniformillumination of LCoS spatial light modulators.

FIGS. 3B-3C are schematic diagrams illustrating example illuminationconfigurations for use in display device 300 in accordance with someembodiments. In FIGS. 3B and 3C, illumination light 390 is transmittedthrough an optical assembly 360 (e.g., one or more optical components)toward a polarizing beam splitter (PBS) 362-1 or 362-2. The PBS 362-1 or362-2 provides the illumination light 390 in a first direction towards aspatial light modulator 370 (e.g., a reflective spatial light modulator,such as an LCoS spatial light modulator), receives modulated light 392output from the spatial light modulator 370, and provides the modulatedlight 392 in a second direction that is different from (e.g.,non-parallel to) the first direction. In some embodiments, the firstdirection and the second direction form an angle that is between 30degrees and 150 degrees, between 45 degrees and 135 degrees, or between60 degrees and 120 degrees. In FIG. 3B, the illumination light 390 istransmitted through PBS 362-1 (e.g., without a change in direction).Additionally, the modulated light 392, output from the spatial lightmodulator 370, is reflected by PBS 362-1 toward an output assembly 372(e.g., display optics or a waveguide with an optical input coupler). InFIG. 3C, the illumination light 390 is reflected by PBS 362-2 toward thespatial light modulator 370 and the modulated light 392, output from thespatial light modulator 370, is transmitted through PBS 362-2 towardoutput assembly 372 (e.g., without a change in direction).

Although FIGS. 4A, 4F-4J, 5A-5D, 6A-6E, and 7 illustrate devices with aconfiguration similar to the configuration shown in FIG. 3B (an opticalaxis of the optical assembly 360 is parallel to an optical axis of thespatial light modulator 370), the optical components in FIGS. 4A, 4F-4J,5A-5D, 6A-6E, and 7 may be arranged so that the optical components arein a configuration similar to the configuration shown in FIG. 3C (theoptical axis of the optical assembly 360 is non-parallel (e.g.,perpendicular) to the optical axis of the spatial light modulator 370).For brevity, the detailed description of such configurations is omittedherein.

FIGS. 4A, 4F-4J, 5A-5D, 6A-6E, and 7 illustrate example optical devicesthat enable a compact illuminator in accordance with some embodiments.Such optical devices may be used to illuminate a spatial light modulator(e.g., reflective spatial light modulator), such as an LCoS spatiallight modulator. In some embodiments, such optical devices are separatefrom the spatial light modulator. In some embodiments, such opticaldevices include the spatial light modulator (e.g., the spatial lightmodulator is integrated into the optical device).

FIG. 4A is a schematic diagram illustrating a display device 400 thatincludes an optical assembly 430 in accordance with some embodiments.Display device 400 includes a light source 410 and a spatial lightmodulator 420 (e.g., a reflective spatial light modulator) so that theoptical assembly 430 is disposed between the light source 410 and thespatial light modulator 420. The light source 410 is configured toprovide (e.g., generate, emit, output, or direct) illumination light 490toward the optical assembly 430. The optical assembly 430 includes afirst reflective surface 430-1 and a second reflective surface 430-2that is separate from (e.g., opposite to) the first reflective surface430-1. The first reflective surface 430-1 is configured to receive theillumination light 490 and to transmit at least a first portion 490-1 ofthe illumination light 490 so that the at least the first portion 490-1of the illumination light 490 is (i) transmitted through the firstreflective surface 430-1 toward the second reflective surface 430-2,(ii) reflected by the second reflective surface 430-2 toward the firstreflective surface 430-1, (iii) reflected by the first reflectivesurface 430-1 toward the second reflective surface 430-2, and (iv)transmitted through the second reflective surface 430-2.

In some embodiments, at least one of the first reflective surface 430-1or the second reflective surface 430-2 is curved. In FIG. 4A, the firstreflective surface 430-1 is curved and the second reflective surface430-2 is not curved (e.g., flat). Alternatively, the first reflectivesurface 430-1 may be flat and the second reflective surface 430-2 may becurved. The radius of curvature of the first reflective surface 430-1and/or the second reflective surface 430-2 contributes to an opticalpower to change a divergence of (e.g., focus or defocus) the firstportion 490-1 of the illumination light 490 when the illumination light490 is directed from the light source 410 to the spatial light modulator420 via the optical assembly 430.

In some embodiments, the display device 400 also includes PBS 440 thatis configured to receive the first portion 490-1 of the illuminationlight 490 and provide the first portion 490-1 of the illumination light490 toward the spatial light modulator 420. In some embodiments, asshown, the optical assembly 430 is disposed between the light source 410and the PBS 440 such that the first reflective surface 430-1 faces thelight source 410 and the second reflective surface 430-2 faces the PBS440.

In some embodiments, the spatial light modulator 420 is an LCoS spatiallight modulator.

In some embodiments, the first reflective surface 430-1 is a partialreflector (e.g., a 50/50 mirror). In some configurations, the firstreflective surface 430-1 is a reflective polarizer that is configured toselectively transmit or reflect light based on the polarization of thelight. For example, a reflective polarizer may be configured to transmitlight having a first polarization and reflect light having a secondpolarization that is different from (e.g., orthogonal to) the firstpolarization.

In some embodiments, the second reflective surface 430-2 is a liquidcrystal based polarization selective element 450 (e.g., a polarizationsensitive hologram, a cholesteric liquid crystal, etc.). Examples of aliquid crystal based polarization selective element 450 include apolarization selective element that includes a metasurface, apolarization selective element that includes a resonant structuredsurface, a polarization selective element that includes a continuouschiral layer, and a polarization selective element that includes abirefringent material. The liquid crystal based polarization selectiveelement 450 may be configured to reflect light having a firstpolarization and transmit light having a second polarization that isdifferent from (e.g., orthogonal to) the first polarization. In someembodiments, the first polarization is a first circular polarization andthe second polarization is a second circular polarization that isorthogonal to the first polarization.

FIGS. 4B-4E illustrate polarization selective element 450 in accordancewith some embodiments.

In some embodiments, polarization selective element 450 includes a layerof liquid crystals arranged in helical structures (e.g., a liquidcrystal formed of a cholesteric liquid crystal). In some embodiments,polarization selective element 450 is polarization selective withrespect to circular polarization of light. When the circularly polarizedlight has a handedness that corresponds to (e.g., is along or has thesame handedness as) the helical twist of liquid crystal structures alongtheir helical axis in polarization selective element 450, polarizationselective element 450 interacts with the circularly polarized light,resulting in change of the direction of propagation of the light (e.g.,reflect, refract, or diffract the light). In contrast, polarizationselective element 450 will transmit light that has a circularpolarization with opposite handedness to the helical twist of liquidcrystal structures in polarization selective element 450 withoutchanging its direction or polarization. Polarization selective element450 can be configured to redirect light having certain propertieswithout changing its polarization while light not having the certainproperties is transmitted through the polarization selective element 450without having its polarization changed.

For example, polarization selective element 450 can have right-handedliquid crystal helical structures and can be configured to redirect(e.g., reflect, refract, diffract) RCP light impinged thereon withoutchanging the polarization of the RCP light while transmitting LCP lightimpinged thereon without changing its polarization or direction. Inaddition to polarization selectivity, polarization selective element 450may also have wavelength selectivity. For example, a right-handedpolarization selective element 450 is configured to reflect RCP lightwithin a certain spectral range and to transmit all other light,including LCP light within the certain spectral range and RCP light thathas a wavelength outside of the certain spectral range. Further,polarization selective element 450 may also be configured to haveangular selectivity such that the polarization selective element 450interacts with light that is incident upon a surface of the polarizationselective element 450 within a certain angular range (e.g.,substantially parallel to an optical axis of the polarization selectiveelement 450, in some cases, the incident light and an optical axis ofthe polarization selective element 450 form an angle that is less than20 degrees) and satisfies the polarization and wavelength conditions asdescribed above. Light that is incident on the surface of thepolarization selective element 450 at an angle that is outside thecertain angular range would be transmitted through the polarizationselective element 450 with no change in polarization or direction.

FIG. 4B illustrates an x-z cross-sectional view of polarizationselective element 450. In some embodiments, polarization selectiveelement 450 includes photoalignment layer 452 (e.g., a layer includingorganic or inorganic compounds including photosensitive groups) andhelical structures 454 formed of optically anisotropic molecules.Photoalignment layer 452 is formed by adding a layer of photoalignmentmaterial (PAM). The PAM layer is then exposed to an alignment light(e.g., linearly polarized light) with a desired intensity and incidentangle. The alignment light is gradually scanned over the layer of PAMwhile rotating polarization of the alignment light. The alignment lightcreates a cycloidal pattern on the layer of PAM (e.g., cycloidalpatterns are explained below with respect to FIG. 5E). After preparationof photoalignment layer 452, a layer of optically anisotropic moleculesis applied onto photoalignment layer 452 forming helical structures 454.The cycloidal pattern of photoalignment layer 452 defines theorientation of helical structures 454. After formation of helicalstructures 454, the layer of optically anisotropic molecules is firmed(e.g., fixed, set, or cured) to form a polymer. In some embodiments, thefirming includes thermal or UV curing. In some embodiments, helicalstructures 454 are formed of liquid crystals, such as cholesteric liquidcrystals. Helical structures 454 are aligned along helical axes 456which is substantially parallel to the z-axis (e.g., helical axes 456and the z-axis form an angle that is no greater than 20 degrees). Insome embodiments, the optically anisotropic molecules are rotated in asame rotational direction (forming a helical twist) about helical axes456 throughout the optically transparent substrate. Helical structures454 define helical pitch 466, used herein to refer to a distance betweentwo adjacent optically anisotropic molecules of a same helical structurethat have the same orientation.

Polarization selective element 450 may change or affect the directionand/or polarization of light in a certain spectral range (e.g.,polarization selective element 450 is wavelength selective) and having afirst circular polarization (e.g., polarization selective element 450 ispolarization selective) that has the same handedness as the helicalstructures in polarization selective element 450. Polarization selectiveelement 450 does not change or affect the direction and polarization oflight outside the certain spectral range and/or having a second circularpolarization opposite to the handedness of the helical structures inpolarization selective element 450. When first incident light having thefirst circular polarization and a wavelength in the certain spectralrange impinges upon polarization selective element 450, polarizationselective element 450 interacts with the first incident light andchanges the direction of the first incident light (e.g., redirects,reflects, refracts, diffracts the first incident light). Whileinteracting with the first incident light, polarization selectiveelement 450 does not change the polarization of the first incident light(e.g., RCP light is reflected as RCP light). On the other hand,polarization selective element 450 is configured to transmit secondincident light that has a wavelength outside the certain spectral rangeassociated with polarization selective element 450 and/or having acircular polarization with handedness opposite to the helical structuresin polarization selective element 450 without changing its direction orpolarization. For example, polarization selective element 450 changesthe direction of the first incident light (RCP) without changing itspolarization and transmits second incident light (LCP) without changingits direction or polarization. In contrast, a conventional reflectivelens or a mirror changes the polarization of polarized incident lightwhen reflecting the light. In some embodiments, in addition to beingselective based on the circular polarization of light, polarizationselective element 450 is also wavelength selective and/or selectivebased on incident angle of the light. Optical properties of polarizationselective element 450 are based on an orientation of the helical axesand/or a helical pitch of a liquid crystal.

FIG. 4C is a cross-sectional view of an x-y plane of polarizationselective element 450. The helical structures 454 in polarizationselective element 450 form lateral fringes (e.g., lateral fringes 460-1and 460-2) that correspond to adjacent optically anisotropic moleculesin the x-y plane that have the same alignment. A lateral pitch 462 isdefined by the distance between two adjacent lateral fringes (e.g.,lateral fringes 460-1 and 460-2).

FIG. 4D is a cross-sectional view of a x-z plane of polarizationselective element 450 across reference plane AA′ illustrated in FIG. 4C.The helical structures 454 in polarization selective element 450 formhelical fringes (e.g., helical fringes 464-1 and 464-2) that correspondto adjacent optically anisotropic molecules in the x-z plane that havethe same alignment. The helical pitch 466 is defined by the distancebetween two adjacent helical fringes (e.g., helical fringes 464-1 and464-2). In some embodiments, as shown, the helical fringes are tilted atan angle α with respect to a surface of polarization selective element450. Arrow 458 illustrates a direction of incident light uponpolarization selective element 450.

FIG. 4E illustrates an exemplary example of the orientation of opticallyanisotropic molecules on a photoalignment layer (e.g., photoalignmentlayer 452). FIG. 4E shows two adjacent optically anisotropic moleculesthat have the same orientation (e.g., optically anisotropic molecules459-1 and 459-2). The distance between optically anisotropic molecules459-1 and 459-2 define the lateral pitch 462, also shown in FIG. 4C.

FIGS. 4F-4J are schematic diagrams illustrating a display device 400that includes an optical assembly 430 in accordance with someembodiments.

In some configurations, as shown in FIG. 4F, a reflective polarizer431-1 and an optical retarder 431-2 (e.g., quarter wave-plate) areadjacent to the second reflective surface 430-2. The reflectivepolarizer 431-1 is configured to selectively transmit or reflect lightbased on the polarization of the light and the optical retarder 431-2(e.g., quarter wave-plate) is positioned to transmit light whileconverting the polarization of the light. For example, the reflectivepolarizer 431-1 may be configured to reflect light having a thirdpolarization and transmit light having a fourth polarization that isdifferent from (e.g., orthogonal to) the third polarization. In someembodiments, the third polarization is a first linear polarization(e.g., s-polarization) and the fourth polarization is a second linearpolarization (e.g., p-polarization) that is orthogonal to the firstpolarization. In some configurations, the optical retarder 431-2 ispositioned to transmit and convert light having a linear polarization tolight having a circular polarization, or vice versa.

FIG. 4F illustrates an optical path of light transmitted through opticalassembly 430 in accordance with some embodiments. In FIG. 4F, the firstreflective surface 430-1 receives the illumination light 490, outputfrom the light source 410, and transmits at least a portion of theillumination light 490 toward the second reflective surface 430-2. Asshown in inset A1 of FIG. 4F, the second reflective surface 430-2reflects at least a portion, of the received illumination light, havinga first polarization (e.g., a first circular polarization) toward thefirst reflective surface 430-1. The first reflective surface 430-1receives the reflected portion of the illumination light 490 andreflects at least a portion of the received light toward the secondreflective surface 430-2 so that the reflected portion of theillumination light 490 has a second polarization that is different from(e.g., orthogonal to) the first polarization. The second reflectivesurface 430-2 transmits the at least a portion 490-1 of the illuminationlight 490 (or a portion thereof) reflected from the first reflectivesurface 430-1.

Inset A2 of FIG. 4F illustrates additional details regarding the opticalpath and polarization of the illumination light 490 at the secondreflective surface 430-2 when a reflective polarizer 431-1 and anoptical retarder 431-2 (e.g., a quarter wave-plate) are located adjacentto the second reflective surface 430-2. In some embodiments, opticalretarder 431-2 is a coating on the second reflective surface 430-2.Alternatively, the optical retarder 431-2 may be an optical element thatis spaced apart from the second reflective surface 430-2. As shown ininset A2, the optical retarder 431-2 receives at least a portion of theillumination light 490 transmitted through the first reflective surface430-1. The optical retarder 431-2 transmits a portion of theillumination light 490 toward the reflective polarizer 431-1 whileconverting the polarization of the portion of the illumination light 490from the first polarization to a third polarization (e.g., from a firstcircular polarization to a first linear polarization). The thirdpolarization is different from each of the first polarization and thesecond polarization. The reflective polarizer 431-1 is configured toreflect at least a portion of the illumination light 490 having thethird polarization back toward the optical retarder 431-2. The opticalretarder 431-2 transmits at least a portion of the reflected lighttoward the first reflective surface 430-1 while converting thepolarization of the at least a portion of the reflected light from thethird polarization to the first polarization. The first reflectivesurface 430-1 reflects at least a portion of the reflected light havingthe first polarization, toward the optical retarder 431-2 so that aportion of the light reflected by the first reflective surface 430-1 hasthe second polarization. The optical retarder 431-2 transmits at least aportion 490-1 of the light having the second polarization toward thereflective polarizer 431-1 while converting the polarization of at leasta portion of the received light from the second polarization to a fourthpolarization (e.g., a second linear polarization) that is different fromeach of the first polarization, the second polarization, and the thirdpolarization. The reflective polarizer 431-1 transmits at least aportion 490-1 of the received light having the fourth polarization.

In some embodiments, the first polarization is a first circularpolarization (e.g., right-hand circular polarization), the secondpolarization is a second circular polarization (e.g., left-hand circularpolarization) that is orthogonal to the first polarization (or viceversa), the third polarization is a first linear polarization (e.g.,s-polarization), and the fourth polarization is a second linearpolarization (e.g., p-polarization) that is orthogonal to the thirdpolarization (or vice versa).

In the ideal case, each optical element and surface has zero ornegligible loss. However, in practice, it is understood that some amountof light (such as the illumination light 490) may be lost throughinteraction with an optical element or surface (such as transmissionthrough an optical surface or reflection at an optical surface).

FIGS. 4G-4J are schematic diagrams illustrating a display device 402that includes an optical assembly 432 in accordance with someembodiments. Display device 402 is similar to display device 400 exceptthat optical assembly 430 is replaced by optical assembly 432. Opticalassembly 432 is similar to optical assembly 430 except that the firstreflective surface 432-1 of optical assembly 432 defines an aperture 434(e.g., a physical through-hole or a window, such as a portion of asurface without a reflective coating where the rest of the surfaceincludes a reflective coating).

In some embodiments, the first reflective surface 432-1 includes a firstportion 432-1A that includes a reflective coating and a second portion432-1B that does not include the reflective coating. The first portion432-1A surrounds the second portion 432-1B and the second portion 432-1Bcorresponds to the aperture 434 (e.g., the aperture 434 is a hole in areflective coating of the first reflective surface 432-1). In FIG. 4G,the first portion 432-1A is illustrated with a solid line and the secondportion 432-1B is illustrated with a dashed line.

In some embodiments, as shown in FIG. 4G, the optical assembly 432 isdisposed between the light source 410 and the spatial light modulator420 (e.g., a reflective spatial light modulator). In such cases, thelight source 410 is aligned (e.g., coupled) with the aperture 434 in thefirst reflective surface 432-1 of the optical assembly 432 so that atleast a portion (e.g., a first portion 490-1) of the illumination light490 is transmitted through the aperture 434 of the first reflectivesurface 432-1 toward the second reflective surface 432-2.

In some embodiments, the second reflective surface 430-2 may be a liquidcrystal based polarization selective element 450 (e.g., a polarizationsensitive hologram, a cholesteric liquid crystal, etc.). Alternatively,the second reflective surface 430-2 may include a reflective polarizerand an optical retarder (e.g., quarter wave-plate), as described abovewith respect to inset A2 in FIG. 4F.

FIG. 4H illustrates an optical path of light transmitted through opticalassembly 432 in accordance with some embodiments, such as when theoptical assembly 432 is disposed between the light source 410 and thespatial light modulator 420. As shown in inset B of FIG. 4H, the firstreflective surface 432-1 receives the illumination light 490, outputfrom the light source 410, and transmits at least a portion of theillumination light 490 through the aperture 434 toward the secondreflective surface 432-2. The second reflective surface 432-2 reflectsat least a portion of the received light back toward the firstreflective surface 432-1 so that the portion of the reflected light hasthe first polarization. The first reflective surface 432-1 reflects atleast a portion of the light reflected by the second reflective surface432-2 back toward the second reflective surface 432-2 so that theportion of the light reflected by the first reflective surface 432-1 hasthe second polarization. The second reflective surface 432-2 transmitsat least a portion 490-1 of the light that was reflected at the firstreflective surface 432-1.

In some embodiments, a reflective polarizer and an optical retarder arelocated adjacent to the second the second reflective surface 432-2, asdescribed above with respect to inset A2 of FIG. 4F.

Compared to the optical path of the illumination light 490 transmittedthrough optical assembly 430, the illumination light 490 transmittedthrough optical assembly 432 is not transmitted through the firstportion of the first reflective surface 432-1 that includes a reflectivecoating, but rather transmitted via the aperture 434 (as shown in FIG.4H) toward the second reflective surface (as shown in FIG. 4F). In somecases, this eliminates any loss associated with transmission through thethird reflective surface 533-1 and allows optical assembly 432 to have ahigher transmission efficiency (e.g., lower loss) than the opticalassembly 430.

In some embodiments, the aperture 434 is a physical hole in the firstreflective surface 432-1. In some cases, as shown in FIG. 4I, at least aportion of the light source 410 may be disposed inside the aperture 434.

FIG. 4J illustrates an optical path of light transmitted through opticalassembly 432 in accordance with some embodiments, such as when at leasta portion of the light source 410 is disposed inside the aperture 434.As shown in inset C of FIG. 4J, the light source 410 outputs theillumination light 490 toward the second reflective surface 432-2. Thesecond reflective surface 432-2 reflects at least a portion of theillumination light 490 back toward the first reflective surface 432-1 sothat the reflected illumination light 490 has the first polarization.The first reflective surface 432-1 reflects at least a portion of thelight reflected by the second reflective surface 432-2 back toward thesecond reflective surface 432-2 so that the portion of the lightreflected by the first reflective surface 432-1 has the secondpolarization. The second reflective surface 432-2 transmits at least aportion 490-1 of the light that was reflected at the first reflectivesurface 432-1.

When the second reflective surface 432-2 includes a reflective polarizerand an optical retarder, details regarding the optical path andpolarization of light at the second reflective surface 432-2 are thesame as described above with respect to inset A2 of FIG. 4F.

FIG. 5A is a schematic diagram illustrating a display device 500 thatincludes an optical assembly 530 in accordance with some embodiments.Display device 500 is similar to display device 400 except that opticalassembly 430 is replaced by optical assembly 530. Optical assembly 530includes a first reflective surface 530-1, a second reflective surface530-2, and a third reflective surface 530-3. The first reflectivesurface 530-1 is disposed between the second reflective surface 530-2and the third reflective surface 530-3.

FIG. 5B is a schematic diagram illustrating optical paths in opticalassembly 530. The arrows shown in FIG. 5B represent relative directionof light propagation among the surfaces of optical assembly 530 (e.g.,from the third reflective surface 530-3 to the first reflective surface530-1, etc.) and are not indicative of geometric directions of raysreflected or transmitted through optical assembly 530 (e.g., FIG. 5B isnot a ray tracing diagram). The optical assembly 530 is configured toreceive the illumination light 490 at the third reflective surface530-3. The third reflective surface 530-3 is configured to transmit atleast a first portion 490-1 of the illumination light 490 and the firstportion 490-1 of the illumination light 490 is (i) transmitted throughthe first reflective surface 530-1 toward the second reflective surface530-2, (ii) reflected by the second reflective surface 530-2 toward thefirst reflective surface 530 1, (iii) reflected by the first reflectivesurface 530-1 toward the second reflective surface 530-2, and (iv)transmitted through the second reflective surface 530-2. The thirdreflective surface 530-3 is also configured to transmit at least asecond portion 490-2 of the illumination light 490 and the secondportion 490-2 of the illumination light 490 is (i) reflected at thefirst reflective surface 530-1 toward the third reflective surface530-3, (ii) reflected by the third reflective surface 530-3 toward thefirst reflective surface 530-1, and (iii) transmitted through the firstreflective surface 530-1 and the second reflective surface 530-2.

In some embodiments, the first reflective surface 530-1 is a partialreflector (e.g., a 50/50 mirror).

In some embodiments, a liquid crystal based polarization selectiveelement similar to the liquid crystal based polarization selectiveelement 450 described above with respect to FIGS. 4B-4E may be disposedadjacent to the second reflective surface 530-2.

In some embodiments, a liquid crystal based polarization selectiveelement similar to the liquid crystal based polarization selectiveelement 450 described above with respect to FIGS. 4B-4E may be disposedadjacent to the third reflective surface 530-3.

In some embodiments, each of the second reflective surface 530-2 and thethird reflective surface 520-3 is curved and the first reflectivesurface 530-1 is not curved (e.g., flat). The radius of curvature of thesecond reflective surface 530-2 contributes to an optical power of thefirst portion 490-1 of the illumination light 490 that is directed fromthe light source 410 to the spatial light modulator 420 via the opticalassembly 530 and the radius of curvature of the third reflective surface530-3 contributes to an optical power of the second portion 490-2 of theillumination light 490 that is directed from the light source 410 to thespatial light modulator 420 via the optical assembly 530. Thus, in someembodiments, each of the second reflective surface 530-2 and the thirdreflective surface 520-3 has a same radius of curvature. In someembodiments, the first portion 490-1 and the second portion 490-2 of theillumination light 490 are directed from the light source 410 to thespatial light modulator 420 via optical assembly 530 at a same opticalpower.

The optical paths of the first portion 490-1 and the second portion490-2 of the illumination light 490 are shown in FIG. 5B. As shown ininset D of FIG. 5B, the third reflective surface 530-3 receives theillumination light 490, output from the light source 410 and having thefirst polarization, and transmits the illumination light 490 toward thefirst reflective surface 530-1. The first reflective surface 530-1transmits a first portion 490-1 of the illumination light 490 toward thesecond reflective surface 530-2 and reflects a second portion 490-2 ofthe illumination light 490 toward the third reflective surface 530-3such that the first portion 490-1 of the illumination light 490transmitted through the first reflective surface 530-1 has the firstpolarization and the second portion 490-2 of the illumination light 490reflected by the first reflective surface 530-1 has the secondpolarization.

Referring to the first portion 490-1 of the illumination light 490, thesecond reflective surface 530-2 is configured to reflect the firstportion 490-1 of the illumination light 490 back toward the firstreflective surface 530-1 without a change in polarization. The firstreflective surface 530-1 receives the first portion 490-1 of theillumination light 490 having the first polarization, and reflects thefirst portion 490-1 of the illumination light 490 toward the secondreflective surface 530-2 so that the reflected first portion 490-1 ofthe illumination light 490 has the second polarization. The secondreflective surface 530-2 transmits the first portion 490-1 of theillumination light 490 having the second polarization.

Referring to the second portion 490-2 of the illumination light 490, thethird reflective surface 530-3 is configured to reflect the secondportion 490-2 of the illumination light 490 having the secondpolarization back toward the first reflective surface 530-1 so that thereflected second portion 490-2 of the illumination light 490 has thesecond polarization (e.g., without a change in polarization). The firstreflective surface 530-1 transmits the second portion 490-2 of theillumination light 490 having the second polarization toward secondreflective surface 530-2, and the second reflective surface 530-2transmits the second portion 490-2 of the illumination light 490 thathas been transmitted through the first reflective surface 530-1.

In some embodiments, a reflective polarizer and an optical retarder arelocated adjacent to the second reflective surface 530-2, as describedabove with respect to inset A2 of FIG. 4F.

Compared to the optical path of the illumination light 490 transmittedthrough optical assembly 430, the illumination light 490 transmittedthrough optical assembly 530 allows a portion (e.g., the second portion490-2) of the illumination light 490 that is not initially transmittedthrough the first reflective surface 530-1 to be redirected toward thefirst reflective surface 530-1, thereby reducing loss. Thus, the opticalassembly 530 may have a higher transmission efficiency (e.g., lowerloss) compared to the optical assembly 430.

FIGS. 5C-5D are schematic diagrams illustrating a display device 502that includes an optical assembly 532 in accordance with someembodiments. Display device 502 is similar to display device 500 exceptthat optical assembly 530 is replaced by optical assembly 532. Opticalassembly 532 is similar to optical assembly 530 except that the thirdreflective surface 532-3 of optical assembly 532 defines an aperture 534(e.g., a physical through-hole or a window, such as a portion of asurface without a reflective coating where the rest of the surfaceincludes a reflective coating).

In some embodiments, as shown in FIG. 5C, the optical assembly 532 isdisposed between the light source 410 and the spatial light modulator420 (e.g., a reflective spatial light modulator). In such cases, thelight source 410 is aligned (e.g., coupled) with the aperture 534 in thethird reflective surface 532-3 of the optical assembly 532 so that atleast a portion (e.g., first portion 490-1 and second portion 490-2) ofthe illumination light 490 is transmitted through the aperture 534 ofthe third reflective surface 532-3 toward the first reflective surface532-1. In such cases, the optical path and polarization of theillumination light 490 in the optical assembly 532 are similar to theoptical path of the illumination light 490 in the optical assembly 530except that the illumination light 490 is transmitted through theaperture 534 of the third reflective surface 532-3.

In some embodiments, the third reflective surface 532-3 includes a firstportion that includes reflective coating and a second portion that doesnot include the reflective coating. The first portion surrounds thesecond portion and the second portion corresponds to the aperture 534(e.g., the aperture 534 is a hole in a reflective coating of the thirdreflective surface 532-3).

In some embodiments, the aperture 534 is a physical hole in the thirdreflective surface 532-3. In some cases, as shown in FIG. 5D, at least aportion of the light source 410 may be disposed inside the aperture 534.In such cases, the optical path of the illumination light 490 in theoptical assembly 532 is similar to the optical path of the illuminationlight 490 in the optical assembly 530 except that the illumination light490 is output from the light source 410 toward the first reflectivesurface 532-1 and thus, the illumination light 490 is not transmittedthrough the third reflective surface 532-3 prior to being incident uponthe first reflective surface 532-1.

Compared to the optical path of the illumination light 490 transmittedthrough optical assembly 530, the illumination light 490 transmittedthrough optical assembly 532 is not transmitted through the thirdreflective surface 533-1, but rather transmitted via the aperture 534(as shown in FIG. 5C) or directly toward the second reflective surface(as shown in FIG. 5D). In some cases, this eliminates any lossassociated with transmission through the third reflective surface 533-1and allows optical assembly 532 to have a higher transmission efficiency(e.g., lower loss) compared to the optical assembly 530.

FIGS. 6A-6C are schematic diagrams illustrating a display device 600that includes optical assembly 630 in accordance with some embodiments.Display device 600 is similar to display device 400 except that opticalassembly 430 is replaced by optical assembly 630. Optical assembly 630includes an optical element 640 and a curved reflector 650. In someembodiments, the curved reflector 650 includes a reflective polarizerand an optical retarder, as described above with respect to FIGS. 4A and4F. Alternatively, the curved reflector 650 may include a liquid crystalbased polarization selective element 450, details of which are providedabove with respect to FIGS. 4B-4E.

As shown in FIG. 6A, the curved reflector 650 is configured to receivethe illumination light 490 so that at least a portion 490-1 of theillumination light 490 is (i) reflected by the curved reflector 650toward the optical element 640, (ii) is reflected by the optical element640 toward the curved reflector 650, and (iii) is transmitted throughthe curved reflector 650.

In some embodiments, the optical assembly 630 (including both theoptical element 640 and the curved reflector 650) is disposed betweenthe light source 410 and the spatial light modulator 420. In such cases,at least a portion 490-1 of the illumination light 490 is transmittedthrough optical element 640 toward the curved reflector 650 before beingreflected by the curved reflector 650.

In some embodiments, as shown in FIG. 6A, the curved reflector 650 isdisposed on a substrate 652. In some embodiments, the curved reflector650 includes one or more coatings disposed on a surface 652-1 of thesubstrate 652 that faces the optical element 640. For example, thecurved reflector 650 may include a polarization sensitive reflectivecoating and an optical retarder coating, as described above with respectto inset A2 of FIG. 4F. In another example, the curved reflector 650 mayinclude a coating that includes a layer of liquid crystals, such apolarization selective element 450, described above with respect toFigured 4B-4E.

In some embodiments, the optical element 640 includes a reflectivesurface 640-1 that is a partial reflector (e.g., a 50/50 mirror).Alternatively, the reflective surface 640-1 may be a reflectivepolarizer that is configured to selectively transmit or reflect lightbased on the polarization of the light. The reflective surface 640-1 maybe disposed on either a first side 640-A or a second side 640-B of theoptical element 640. In some embodiments, the reflective surface 640-1is a reflective coating or a partially reflective coating.

FIG. 6B illustrates a display device 600, in which the optical element640 defines an aperture 644. In some embodiments, the reflective surface640-1 is a full reflector. In some cases, the light source 410 isaligned (e.g., coupled) with the aperture 644 so that at least a portion490-1 of the illumination light 490 is transmitted through the aperture644 toward the curved reflector 650. In some embodiments, as shown inFIG. 6B, at least a portion of the light source 410 is disposed insidethe aperture 644 of the optical element 640.

In some embodiments, the reflective surface 640-1 includes a firstportion that includes a reflective coating and a second portion thatdoes not include the reflective coating. The first portion surrounds thesecond portion and the second portion corresponds to the aperture 644(e.g., the aperture 644 is a hole in a reflective coating of thereflective surface 640-1).

In some embodiments, the reflective surface 640-1 of the optical element640 is curved. The radius of curvature of each of the curved reflector650 and the reflective surface 640-1 (when curved) contributes to anoptical power of the portion 490-1 of the illumination light 490 that isdirected from the light source 410 to the spatial light modulator 420via the optical assembly 630.

In some embodiments, as shown in FIG. 6A, the optical assembly 630,including the curved reflector 650 and the optical element 640, isdisposed between the light source 410 and the PBS 440.

FIG. 6C illustrates the optical path and the polarization of lighttransmitted through optical assembly 630. As shown in inset E of FIG.6C, the reflective surface 640-1 receives the illumination light 490output from the light source 410, and transmits at least a portion ofthe illumination light 490 toward curved reflector 650. The curvedreflector 650 reflects at least a portion of the illumination light 490,having a first polarization, toward the reflective surface 640-1. Thereflective surface 640-1 receives the at least a portion of theillumination light, having the first polarization, and reflects at leasta portion of the received light toward the curved reflector 650 so thata portion 490-1 of the light reflected by the reflective surface 640-1has the second polarization. The curved reflector 650 transmits at leasta portion 490-1 of the illumination light 490 that was reflected by thereflective surface 640-1.

In some cases, such as when curved reflector 650 is a coating on thesurface 652-1 of the substrate 652, the at least a portion 490-1 of theillumination light 490 is transmitted through the substrate 652.

In some embodiments, in which at least a portion of the light source 410is disposed inside the aperture 644 of the optical element 640, theoptical path of the illumination light 490 is similar to the opticalpath described above except that the illumination light 490 is outputfrom the light source 410 toward the curved reflector 650 and thus, theillumination light 490 is not transmitted through the reflective surface640-1 of the optical element 640 prior to being incident upon the curvedreflector 650.

In some embodiments, the curved reflector 650 includes a reflectivepolarizer and an optical retarder. Details regarding the optical pathand the polarization of light at the curved reflector are similar tothose described above with respect to inset A2 of FIG. 4F. For brevity,such details are not repeated herein.

FIG. 6D illustrates a display device 602 in accordance with someembodiments. Display device 602 is similar to display device 600 exceptthat the optical assembly 630 is replaced with an optical assembly 632.In FIG. 6D, the light source 410 is disposed between the optical element640 and the curved reflector 650. The light source 410 shown in FIG. 6Dis configured to provide (e.g., generate, emit, or output) theillumination light 490 towards the curved reflector 650. The curvedreflector 650 is configured to receive the illumination light 490 andreflect at least a portion of the illumination light 490 to so that atleast a portion 490-1 of the illumination light 490 that is reflected atthe curved reflector 650 is: (i) received by the optical element 640,(ii) reflected by the optical element 640 (e.g., the reflective surface640-1 of the optical element 640) toward curved reflector 650, and (iii)transmitted through the curved reflector 650.

In some embodiments, the light source 410 may not be completely (e.g.,100%) transparent (e.g., optically transparent to the illumination light490). In such cases, when the light source 410 is disposed between thecurved reflector 650 and the optical element 640, the light source 410may block some of the illumination light 490 as the illumination light490 is reflected between the curved reflector 650 and the opticalelement 640. Thus, a portion of the illumination light 490 reflected bythe curved reflector 650 is not received at the optical element 640 anda portion of the illumination light 490 reflected by the optical element640 toward the curved reflector 650 is not received by the curvedreflector 650. In such cases, the at least a portion 490-1 of theillumination light is a subset, less than all, of the illumination lightprovided (e.g., generated, emitted, or output) by the light source 410.

In some embodiments, in which at least a portion of the light source 410is disposed inside the aperture 644 of the optical element 640 (shown inFIG. 6C) or the light source 410 is disposed between the optical element640 and the curved reflector 650, the optical element 640 includes afull reflector (e.g., a mirror, such as a reflector with a reflectancegreater than 80%, 85%, 90%, 95%, 97%, 98%, or 99%). In some embodiments,the reflective surface 640-1 is a full reflector.

The optical path of the illumination light 490 in optical assembly 632is similar to the optical path of the illumination light 490 in opticalassembly 630 except that the illumination light 490 is output from thelight source 410 toward the curved reflector 650 and thus, theillumination light 490 is not transmitted through the reflective surface640-1 or the optical element 640 prior to being incident upon the curvedreflector 650.

FIG. 6E illustrates a display device 604 in accordance with someembodiments. Display device 604 is similar to display device 600 exceptthat the optical assembly 630 is replaced with an optical assembly 634.In FIG. 6E, the curved reflector 650 is disposed on a substrate 654 thatincludes PBS 440 (e.g., the curved reflector 650 is integrated with PBS440, and the PBS 440 that is included as part of substrate 654 isindicated by a dotted box). In some embodiments, the curved reflector650 is a polarization selective coating disposed on a surface 654-1 ofthe substrate 654 that faces the optical element 640.

The optical path of the illumination light 490 in optical assembly 634is similar to the optical path of the illumination light 490 in opticalassembly 630 except that the illumination light 490 is output from thelight source 410 toward the curved reflector 650 and thus, theillumination light 490 is not transmitted through the reflective surface640-1 or the optical element 640 prior to being incident upon the curvedreflector 650. Additionally, the at least a portion 490-1 of theillumination light 490 that is transmitted through the curved reflectoris coupled into the substrate 654 and PBS 440.

FIG. 7 is a schematic diagram illustrating a display device 700 thatincludes an optical element 730 in accordance with some embodiments.Display device 700 is similar to display device 400 except that opticalassembly 430 is replaced by optical element 730. The optical element 730includes a first reflective surface 730-1 and a second surface 730-2that is opposite to the first reflective surface 730-1. The light source410 is disposed between the optical element 730 and the spatial lightmodulator 420 (e.g., a reflective spatial light modulator), and isconfigured to provide (e.g., generate, emit, or output) illuminationlight 490 towards the optical element 730. The first reflective surface730-1 is configured to receive and reflect the illumination light 490 sothat at least a portion of the illumination light 490 illuminates thespatial light modulator 420.

In some embodiments, as shown, the second surface 730-2 is configured toreceive the illumination light 490 provided (e.g., generated, emitted,or output) by the light source 410 and to transmit the receivedillumination light 490 toward the first reflective surface 730-1. Thefirst reflective surface 730-1 is configured to reflect at least aportion 490-1 of the illumination light, transmitted through the secondsurface 730-2, back toward the second reflective surface 730-2 so thatat least a portion 490-1 of the light reflected by the first reflectivesurface 730-1 is transmitted through the second surface.

In some embodiments, the display device 700 includes PBS 440. In suchcases, the light source 410 is disposed between the optical element 730and the PBS 440 such that the at least a portion 490-1 of theillumination light 490 is received at the PBS 440.

In some embodiments, the light source 410 may not be completely (e.g.,100%) transparent (e.g., optically transparent to the illumination light490). In such cases, the at least a portion 490-1 of the illuminationlight is a subset, less than all, of the illumination light provided(e.g., generated, emitted, or output) by the light source 410.

In some embodiments, as shown in FIG. 7 , the first reflective surface730-1 is curved and has a first radius of curvature. The first radius ofcurvature of the first reflective surface 730-1 contributes, at leastpartially, to an optical power of the at least a portion 490-1 of theillumination light 490 that is directed from the light source 410 to thespatial light modulator 420 via the optical element 730.

In some embodiments, the second surface 730-2 is curved and has a secondradius of curvature that is different from the first radius ofcurvature. Due to refraction (of the illumination light 490 and/or theat least a portion 490-1 of the illumination light 490) at the secondsurface 730-2, the second radius of curvature of the second surface730-2 may contribute, at least partially, to the optical power of the atleast a portion 490-1 of the illumination light 490 that is directedfrom the light source 410 to the spatial light modulator 420 via theoptical element 730.

In some embodiments, the first reflective surface 730-1 is a fullreflector (e.g., mirror). Alternatively, the first reflective surface730-1 may be a partial reflector (e.g., a 50/50 mirror) or a reflectivepolarizer that is configured to selectively transmit or reflect lightbased on the polarization of the light.

In some embodiments, the second surface 730-2 is a non-reflectivesurface (e.g., an optical surface that does not include any reflectiveor partially reflective coatings). In some embodiments, the secondsurface 730-2 may include a non-reflective coating (e.g.,anti-reflection coating) that is configured to reduce loss due toreflection at an optical surface.

FIGS. 8A-8C are schematic diagrams illustrating a light source 800,which corresponds to light source 410 in some embodiments. Light source800 includes a first plurality of light emitting elements 810 (e.g.,LEDs, miniLEDs) that is configured to provide (e.g., generate, emit, oroutput) first light having wavelengths in a first wavelength range(e.g., red light). The light source also includes a plurality ofwaveguides 820. A respective waveguide 820 (e.g., one of waveguides820-1, 820-2, 820-3, . . . , 820-n) of the plurality of waveguides 820includes an input end that is coupled to a respective light emittingelement 810 (e.g., light emitting elements 810-1, 810-2, 810-3, . . . ,810-n) of the first plurality of light emitting elements 810 (e.g., therespective light emitting element 810 is disposed adjacent to or at theinput end of the respective waveguide 820). A respective waveguide 820is configured to transmit the first light output from the respectivelight emitting element 810, so that the first light is output, from anoutput end of the waveguide 820 that is opposite to the input end of thewaveguide 820, as illumination light 490. In some embodiments, theplurality of waveguides 820 is configured to transmit the first lightsuch that the illumination light 490 provides uniform illumination. Forexample, the plurality of waveguides 820 has a particular length forproviding uniform illumination. In some cases, the length of theplurality of waveguides 820 is selected based on a divergence of thelight emitting elements 810. In some embodiments, the plurality ofwaveguides 820 is configured to transmit the first light such that theillumination light 490 output from the light source is collimated (e.g.,a respective waveguide of the plurality of waveguides 820 is tapered toprovide collimated light).

In some embodiments, a distance P1 between two consecutive (e.g.,adjacent) light emitting elements, as shown in FIG. 8A, is between 50microns and 120 microns. For example, when light emitting elements 810are red LEDs or red miniLEDs, the distance P may be less than 60microns, between 50 and 70 microns, between and 60 and 80 microns,between 70 and 90 microns, between 80 and 100 microns, between 90 and110 microns, between 100 and 120 microns, or greater than 110 microns.

In some embodiments, as shown in FIG. 8B, the light source also includesa second plurality of light emitting elements 830 that is configured toprovide (e.g., generate, emit, or output) second light havingwavelengths in a second wavelength range (e.g., green light) that isdifferent from the first wavelength range. A respective waveguide 820 isfurther coupled to a respective light emitting element (e.g., lightemitting elements 830-1, 830-2, 830-3, 830-4) of the second plurality oflight emitting elements 830. The respective waveguide 820 is configuredto transmit the second light provided from the respective light emittingelement of the second plurality of light emitting elements 830. In someembodiments, the plurality of waveguides 820 is configured to transmiteach of the first light and the second light such that the illuminationlight 490 provides uniform illumination. In some embodiments, theplurality of waveguides 820 act as homogenizers, allowing each of thefirst and second light to be output from the light source 800.

In some embodiments, the light source further includes a third pluralityof light emitting elements 834 that are configured to provide (e.g.,generate, emit, or output) third light having wavelengths in a thirdwavelength range (e.g., blue light) that is different from each of thefirst wavelength range and the second wavelength range. A respectivewaveguide 820 is further coupled to a respective light emitting element(e.g., light emitting elements 840-1, 840-2, 840-3, 840-4) of the thirdplurality of light emitting elements 840. The respective waveguide 820is configured to transmit the third light provided from the respectivelight emitting element of the third plurality of light emitting elements840. In some embodiments, the plurality of waveguides 820 is configuredto transmit each of the first light, the second light, and the thirdlight such that the illumination light 490 provides uniformillumination. In some embodiments, the plurality of waveguides 820 actsas homogenizers, allowing each of the first, second, and third light toprovide uniform illumination when output from the light source 800. Insome embodiments, the illumination light 490, output from the pluralityof waveguides 820, include each of the first, second, and third light,illustrated by the boxes 812, 832, and 842, respectively.

In some embodiments, a distance P2 between two consecutive (e.g.,adjacent) light emitting elements that are configured to provide lighthaving different wavelength ranges is between 30 microns and 70 microns.For example, when light emitting elements 840 are configured to providered light and light emitting elements 830 are configured to providegreen light, the distance P2 may be less than 30 microns, between 20 and40 microns, between 30 and 50 microns, between 40 and 60 microns,between 50 and 70 microns, between 60 and 80 microns, or greater than 70microns.

Although four waveguides and four light emitting elements are shown foreach of the first plurality of light emitting elements 810, the secondplurality of light emitting elements 830, and the third plurality oflight emitting elements 840, it is understood that the light source 800may include any number of waveguides and light emitting elements.

In some embodiments, the first wavelength range and the secondwavelength range include non-overlapping wavelengths (e.g., the firstwavelength range and the second wavelength range are mutuallyexclusive). For example, the first light may correspond to light havinga red color and the second light may correspond to light having a greencolor. Thus, the first wavelength range may include wavelengths from 635nanometers (nm) to 700 nm and the second wavelength range may includewavelengths from 520 nm-560 nm.

In some embodiments, the first wavelength range and the secondwavelength range include common wavelengths (e.g., the first wavelengthrange and the second wavelength range partially overlap with eachother). For example, the first light may correspond to light having a(primarily or dominantly) blue color and the second light may correspondto light having a (primarily or dominantly) green color. Thus, the firstwavelength range may include wavelengths from 450 nanometers (nm) to 500nm and the second wavelength range may include wavelengths from 490 nmto 570 nm.

For example, any of the first light and the second light may correspondto light having any color, such as red, blue, green, white, yellow,orange, etc. Some examples of wavelength ranges include 420-440 nm(blue), 490 nm-570 nm (green), 570-585 nm (yellow), 585-620 (orange),and 620-780 nm (red). Light source 800 may include light emittingelements that are configured to provide light having any wavelengthrange and are not limited to the examples provided herein.

In some embodiments, the third wavelength range is mutually exclusive tothe first wavelength range and the second wavelength range. In someembodiments, the third wavelength range partially overlaps with thefirst wavelength range or the second wavelength range.

In some embodiments, a respective waveguide 820 of the plurality ofwaveguides 820 is tapered. As shown in FIG. 8C, the input end of arespective waveguide 820 has a first width D1 and the output end of therespective waveguide 820 has a second width D2 that is different from(e.g., greater than) the first width D1. Although FIG. 8C shows that arespective waveguide 820 is coupled to three light emitting elements, itis understood that a respective waveguide 820 may be coupled to anynumber of light emitting elements. Additionally, the respectivewaveguide 820 may have the first width D1 that is equal to or greaterthan a width of the light emitting element(s) that the respectivewaveguide 820 is coupled to. For example, if a light emitting element isa miniLED that has a width of 10 microns and a respective waveguide 820is coupled to the light emitting element, the respective waveguide 820may have a width D1 that is 10 microns or greater. Similarly, if therespective waveguide 820 is coupled to two light emitting elements thateach have a width of 10 microns, the respective waveguide 820 may have awidth D1 that is 20 microns or greater (e.g., 50 microns or greater ifthe two light emitting elements are separated by 30 microns). In someembodiments, the respective waveguide 820 has a cylindrical shape (or aconical shape) and the first width D1 and the second width D2 correspondto a diameter D1 and a diameter D2 of the respective waveguide 820 onboth ends.

In some embodiments, the use of tapered waveguides collimates light.This, in turn, improves an efficiency as light emitted from a lightemitting element can provide uniform intensity over a wider areacompared to light emitted from the same light emitting element via anon-tapered waveguide.

In some embodiments, the tapered waveguide 820 has a linear taperprofile (e.g., the respective waveguide 820 has straight side walls).Alternatively, the respective waveguide 820 may have a non-linear taperprofile, such as a parabolic, curved, or exponential taper profile(e.g., as in a compound parabolic concentrator).

In some embodiments, the waveguide is a planar or slab waveguide andwidths D1 and D2 correspond to distances between the side walls of thewaveguide at respective ends. In some embodiments, the waveguide is anoptical fiber and distances D1 and D2 correspond to diameters of a coreof the optical fiber at respective ends. For example, planar waveguidesmay have side walls that are separated by as little as a few microns(e.g., ˜1-3 microns) or as large as an a few millimeters (1-2millimeters). For example, for an optical fiber may have a core diameterranging from a few microns (e.g., ˜1-3 microns) up to 800 microns orlarger. Some common core diameters are 9 microns, 50 microns, and 62.5microns.

In some embodiments, a respective waveguide 820 may include anextramural absorption element (e.g., extramural layer) for absorbingstray light that may escape from the respective waveguide 820.

FIGS. 9A-9C are flow diagrams illustrating a method 900 of providingshort distance illumination in accordance with some embodiments. Themethod 900 includes (operation 902) outputting illumination light 490from a light source 410, (operation 920) receiving the illuminationlight 490 at a first reflective surface 430-1 or 530-1 of an opticalassembly 430 or 530. The optical assembly 430 or 530 includes a secondreflective surface 430-2 or 530-2 that is located opposite to the firstreflective surface 430-1 or 530-1. The method 900 also includes(operation 922) transmitting a first portion 490-1 of the illuminationlight 490 through the first reflective surface 430-1 or 530-1 toward thesecond reflective surface 430-2 or 530-2; (operation 924) reflecting, atthe second reflective surface 430-2 or 530-2, the first portion 490-1 ofthe illumination light 490 that has been transmitted through the firstreflective surface 430-1 or 530-1; and (operation 926) reflecting, atthe first reflective surface 430-1 or 530-1, the first portion 490-1 ofthe illumination light 490 that has been reflected by the secondreflective surface 430-2 or 530-2 toward the first reflective surface430-1 or 530-1. The method further includes (operation 928)transmitting, through the second reflective surface 430-2 or 530-2, thefirst portion 490-1 of the illumination light 490 reflected by the firstreflective surface 430-1 or 530-1; and (operation 930) receiving thefirst portion of the illumination light at a spatial light modulator(e.g., spatial light modulator 420).

In some embodiments, the light source 800 (corresponding to light source410) includes a first plurality of light emitting elements 810 (e.g.,light emitting elements 810-1, 810-2, 810-3, . . . , 810-n) and aplurality of waveguides 820 (e.g., waveguides 820-1, 820-2, 820-3, . . ., 820-n). In some embodiments, the method 900 includes (operation 904)providing first light having wavelengths in a first wavelength range(e.g., the first light may correspond to light having a red color) froma respective light emitting element of the first plurality of lightemitting elements 810, guiding the first light by a respective waveguideof the plurality of waveguides 820 that is coupled to the respectivelight emitting element of the first plurality of light emitting elements810, and transmitting the first light provided by the respective lightemitting element of the first plurality of light emitting elements 810via (e.g., by) the respective waveguide 820 as at least a portion of theillumination light 490.

In some embodiments, the light source 800 (corresponding to light source410) also includes a second plurality of light emitting elements 830.The method 900 further includes (operation 910) providing second lighthaving wavelengths in a first wavelength range (e.g., the second lightmay correspond to light having a green color) from a respective lightemitting element of the second plurality of light emitting elements 830,guiding the second light by a respective waveguide of the plurality ofwaveguides 820 that is coupled to the respective light emitting elementof the second plurality of light emitting elements 830, and transmittingthe second light provided by the respective light emitting element ofthe second plurality of light emitting elements 830 via (e.g., by) therespective waveguide 820 as at least a portion of the illumination light490.

In some embodiments, the respective waveguide of the plurality ofwaveguides 820 is tapered, illustrated in FIG. 8C.

In some embodiments, the light source includes a plurality of lightemitting elements (e.g., light emitting elements 810-1 through 810-n,light emitting elements 830, and/or light emitting elements 840) and themethod 900 further includes (operation 916) activating a subset, lessthan all, of the plurality of light emitting elements.

In some embodiments, the method 900 further includes (operation 940)transmitting, through a third reflective surface 530-3 of the opticalassembly 530, a first portion 490-1 of the illumination light 490 and asecond portion 490-2 of the illumination light 490 that is distinct fromthe first portion 490-1 of the illumination light 490, illustrated inFIG. 5B. In some embodiments, the method 900 also includes reflectingthe second portion of the illumination light at the first reflectivesurface toward the third surface; reflecting, at the third reflectivesurface 530-3, the second portion 490-2 of the illumination light 490reflected at the first reflective surface 530-1 toward the thirdreflective surface 530-3; transmitting, through the first reflectivesurface 530-1 and the second reflective surface 530-2, the secondportion 490-2 of the illumination light 490 reflected by the thirdreflective surface 530-3; and receiving the second portion 490-2 of theillumination light 490 output from optical assembly 530 at the spatiallight modulator 420.

In some embodiments, the method 900 further includes (operation 950)receiving the first portion 490-1 of the illumination light 490transmitted through the optical assembly 430 or 530 at a beam splitter440 (e.g., PBS 440); providing with the beam splitter 440 the firstportion 490-1 of the illumination light 490 in a first direction towarda spatial light modulator 420; and (operation 952) receiving, at thebeam splitter 440, the first portion 490-1 of the illumination light 490in a first direction toward the spatial light modulator 420.

In some embodiments, modulating least the first portion 490-1 of theillumination light 490 includes (operation 952) reflecting a subset,less than all, of the first portion 490-1 of the illumination light 490.

In some embodiments, the method 900 also includes (operation 960)modulating the second portion 490-2 of the illumination light 490 withthe spatial light modulator 420, outputting the at least the firstportion 490-1 of the illumination light 490 from the spatial lightmodulator 420 as modulated light, outputting the at least the secondportion 490-2 of the illumination light 490 from the spatial lightmodulator 420 as modulated light. In such cases, the modulated lightoutput from the spatial light modulator 420 includes the modulated firstportion 490-1 of the illumination light 490 and the modulated secondportion 490-2 of the illumination light 490. The method 900 alsoincludes providing, by the beam splitter 440, the modulated light in asecond direction that is non-parallel to the first direction.

FIGS. 10A-10C is a flow diagram illustrating a method 1000 of providingshort distance illumination in accordance with some embodiments. Themethod 1000 includes (operation 1002) outputting illumination light 490from a light source 410. The light source 410 is positioned adjacent toa first reflective surface (e.g., first reflective surface 432-1 orthird reflective surface 532-3) of an optical assembly 432 or 532. Thefirst reflective surface (e.g., first reflective surface 432-1 or thirdreflective surface 532-3) defines an aperture 434 or 534, and theoptical assembly 432 or 532 has a second reflective surface (e.g.,second reflective surface 432-2 or first reflective surface 532-1) thatis located opposite to the first reflective surface (e.g., firstreflective surface 432-1 or third reflective surface 532-3). The method1000 also includes (operation 1030) reflecting, at the second reflectivesurface (e.g., second reflective surface 432-2 or first reflectivesurface 532-1), a first portion 490-1 of illumination light 490 towardthe first reflective surface (e.g., first reflective surface 432-1 orthird reflective surface 532-3); (operation 1032) reflecting, at thefirst reflective surface (e.g., first reflective surface 432-1 or thirdreflective surface 532-3), the first portion 490-1 of the illuminationlight 490 that was reflected by the second reflective surface (e.g.,second reflective surface 432-2 or first reflective surface 532-1)toward the first reflective surface (e.g., first reflective surface432-1 or third reflective surface 532-3); (operation 1034) transmitting,through the second reflective surface (e.g., second reflective surface432-2 or first reflective surface 532-1), the first portion 490-1 of theillumination light 490 reflected by the first reflective surface (e.g.,first reflective surface 432-1 or third reflective surface 532-3); and(operation 1036) receiving the first portion 490-1 of the illuminationlight 490 at a spatial light modulator 420.

In some embodiments, at least a portion of the light source 410 isdisposed in the aperture 434 or 534 in the first reflective surface(e.g., first reflective surface 432-1 or third reflective surface532-3).

In some embodiments, the light source 800 (corresponding to light source410) includes a first plurality of light emitting elements 810 (e.g.,light emitting elements 810-1, 810-2, 810-3, . . . , 810-n) and aplurality of waveguides 820 (e.g., waveguides 820-1, 820-2, 820-3, . . ., 820-n). In some embodiments, the method 1000 includes (operation 1006)providing first light having wavelengths in a first wavelength range(e.g., the first light may correspond to light having a red color) froma respective light emitting element of the first plurality of lightemitting elements 810, guiding the first light by a respective waveguideof the plurality of waveguides 820 that is coupled to the respectivelight emitting element of the first plurality of light emitting elements810, and transmitting the first light provided by the respective lightemitting element of the first plurality of light emitting elements 810via (e.g., by) the respective waveguide 820 as at least a portion of theillumination light 490.

In some embodiments, the light source 800 (corresponding to light source410) also includes a second plurality of light emitting elements 830.The method 1000 further (operation 1010) includes providing second lighthaving wavelengths in a first wavelength range (e.g., the second lightmay correspond to light having a green color) from a respective lightemitting element of the second plurality of light emitting elements 830,guiding the second light by a respective waveguide of the plurality ofwaveguides 820 that is coupled to the respective light emitting elementof the second plurality of light emitting elements 830, and transmittingthe second light provided by the respective light emitting element ofthe second plurality of light emitting elements 830 via (e.g., by) therespective waveguide 820 as at least a portion of the illumination light490.

In some embodiments, the respective waveguide of the plurality ofwaveguides 820 is tapered, illustrated in FIG. 8C.

In some embodiments, the light source 800 includes a plurality of lightemitting elements (e.g., light emitting elements 810-1 through 810-n,light emitting elements 830, and/or light emitting elements 840). Themethod 1000 further includes (operation 1014) activating a subset, lessthan all, of the plurality of light emitting elements.

In some embodiments, the method 1000 further includes (operation 1020)includes transmitting the illumination light 490, including the firstportion 490-1 of the illumination light 490, through the aperture 434 or534 in the first reflective surface 432-1 or 532-3 toward the secondreflective surface 432-2 or 532-1.

In some embodiments, the method 1000 further includes (operation 1040)transmitting a second portion 490-2 of the illumination light 490 at thesecond reflective surface (e.g., first reflective surface 532-1) towarda third reflective surface (e.g., second reflective surface 532-2). Thesecond portion 490-2 of the illumination light 490 is distinct from thefirst portion 490-1 of the illumination light 490. The method 1000 alsoincludes reflecting, at the third reflective surface (e.g., secondreflective surface 532-2), the second portion 490-2 of the illuminationlight 490 transmitted through the second reflective surface (e.g., firstreflective surface 532-1) toward the third reflective surface (e.g.,second reflective surface 532-2); reflecting, at the second reflectivesurface (e.g., first reflective surface 532-1), the second portion ofthe illumination light reflected at the third reflective surface (e.g.,second reflective surface 532-2) toward the third reflective surface(e.g., second reflective surface 532-2); and transmitting, through thethird reflective surface (e.g., second reflective surface 532-2), thesecond portion 490-2 of the illumination light 490 reflected by thesecond reflective surface (e.g., first reflective surface 532-1).

In some embodiments, the method 1000 further includes (operation 1050)receiving the first portion 490-1 of the illumination light 490transmitted through the second reflective surface (e.g., secondreflective surface 432-2 or first reflective surface 532-1) at the beamsplitter 440 (e.g., PBS 440). The method 1000 also includes directing,with the beam splitter 440, the first portion 490-1 of the illuminationlight 490 in a first direction toward the spatial light modulator 420;modulating, with the spatial light modulator 420, the first portion490-1 of the illumination light 490; outputting, from the spatial lightmodulator 420, the at least a portion 490-1 of the illumination light490 as modulated light; receiving, at the beam splitter 440, the firstportion 490-1 of the illumination light 490 in a first direction towardthe spatial light modulator 420; and directing, with the beam splitter440, the modulated light in a second direction that is non-parallel tothe first direction.

In some embodiments, modulating the first portion 490-1 of theillumination light 490 with the spatial light modulator 420 includes(operation 1052) reflecting a subset, less than all, of the firstportion 490-1 of the illumination light 490.

FIGS. 11A-11B is a flow diagram illustrating a method 1100 of providingshort distance illumination in accordance with some embodiments. Themethod 1100 includes (operation 1102) outputting illumination light 490from a light source 410, (operation 1130) receiving the illuminationlight 490 at a curved reflector 650, and (operation 1132) reflecting atleast a portion 490-1 of the illumination light 490 at the curvedreflector 650. The method also includes (operation 1134) reflecting, atan optical element 640, the at least a portion 490-1 of the illuminationlight 490 reflected at the curved reflector 650; (operation 1136)transmitting, through the curved reflector 650, the at least a portion490-1 of the illumination light 490 reflected by the optical element640; and (operation 1138) receiving the at least a portion 490-1 of theillumination light 490 at a spatial light modulator 420.

In some embodiments, the light source 800 (corresponding to light source410) includes a first plurality of light emitting elements 810 (e.g.,light emitting elements 810-1, 810-2, 810-3, . . . , 810-n) and aplurality of waveguides 820 (e.g., waveguides 820-1, 820-2, 820-3, . . ., 820-n). In some embodiments, the method 1100 includes (operation 1104)providing first light having wavelengths in a first wavelength range(e.g., the first light may correspond to light having a red color) froma respective light emitting element of the first plurality of lightemitting elements 810, guiding the first light by a respective waveguideof the plurality of waveguides 820 that is coupled to the respectivelight emitting element of the first plurality of light emitting elements810, and transmitting the first light provided by the respective lightemitting element of the first plurality of light emitting elements 810via (e.g., by) the respective waveguide 820 as at least a portion of theillumination light 490.

In some embodiments, the light source 800 (corresponding to light source410) also includes a second plurality of light emitting elements 830.The method 1100 further includes (operation 1112) providing second lighthaving wavelengths in a first wavelength range (e.g., the second lightmay correspond to light having a green color) from a respective lightemitting element of the second plurality of light emitting elements 830,guiding the second light by a respective waveguide of the plurality ofwaveguides 820 that is coupled to the respective light emitting elementof the second plurality of light emitting elements 830, and transmittingthe second light provided by the respective light emitting element ofthe second plurality of light emitting elements 830 via (e.g., by) therespective waveguide 820 as at least a portion of the illumination light490.

In some embodiments, the respective waveguide of the plurality ofwaveguides 820 is tapered, illustrated in FIG. 8C.

In some embodiments, the light source 800 includes a plurality of lightemitting elements (e.g., light emitting elements 810-1 through 810-n,light emitting elements 830, and/or light emitting elements 840). Themethod 1100 further includes (operation 1122) activating a subset, lessthan all, of the plurality of light emitting elements.

In some embodiments, the optical element 640 is disposed relative to thelight source 410 and the method 1100 further includes (operation 1124)transmitting the at least a portion 490-1 of the illumination light 490through the optical element 640 toward the curved reflector 650.

In some embodiments, the optical element 640 defines an aperture 644.The method 1100 further includes (operation 1126) transmitting the atleast a portion 490-1 of the illumination light 490 through the aperture644 of the optical element 640 toward the curved reflector 650. Theoptical element 640 defines the aperture 644.

In some embodiments, the method 1100 further includes (operation 1140)receiving, at a beam splitter 440 (e.g., PBS 440), the at least aportion 490-1 of the illumination light 490 transmitted through thecurved reflector 650; providing, with the beam splitter 440, the atleast a portion 490-1 of the illumination light 490 in a first directiontoward the spatial light modulator 420; modulating, the at least aportion 490-1 of the illumination light 490 with the spatial lightmodulator 420; outputting the at least a portion 490-1 of theillumination light 490 from the spatial light modulator 420 as modulatedlight; receiving the modulated light output from the spatial lightmodulator 420; and providing, by the beam splitter 440, the modulatedlight in a second direction that is non-parallel to the first direction.

In some embodiments, modulating the at least a portion 490-1 of theillumination light 490 with the spatial light modulator 420 includes(operation 1146) reflecting a subset, less than all, of the at least aportion 490-1 of the illumination light 490.

FIGS. 12A-12B is a flow diagram illustrating a method 1200 of providingshort distance illumination in accordance with some embodiments. Themethod 1200 includes (operation 1202) outputting illumination light 490from a light source 410, (operation 1220) receiving at least a portion490-1 of the illumination light 490 at a reflective surface 730-1 of anoptical element 730, (operation 1230) reflecting the at least a portion490-1 of the illumination light 490 at the reflective surface 730-1, and(operation 1240) receiving the at least a portion 490-1 of theillumination light 490 at a spatial light modulator 420.

In some embodiments, the light source 800 (corresponding to light source410) includes a first plurality of light emitting elements 810 (e.g.,light emitting elements 810-1, 810-2, 810-3, . . . , 810-n) and aplurality of waveguides 820 (e.g., waveguides 820-1, 820-2, 820-3, . . ., 820-n). In some embodiments, the method 1200 includes (operation 1210)providing first light having wavelengths in a first wavelength range(e.g., the first light may correspond to light having a red color) froma respective light emitting element of the first plurality of lightemitting elements 810, guiding the first light by a respective waveguideof the plurality of waveguides 820 that is coupled to the respectivelight emitting element of the first plurality of light emitting elements810, and transmitting the first light provided by the respective lightemitting element of the first plurality of light emitting elements 810via (e.g., by) the respective waveguide 820 as at least a portion of theillumination light 490.

In some embodiments, the light source 800 (corresponding to light source410) also includes a second plurality of light emitting elements 830.The method 1200 further includes (operation 1212) providing second lighthaving wavelengths in a first wavelength range (e.g., the second lightmay correspond to light having a green color) from a respective lightemitting element of the second plurality of light emitting elements 830,guiding the second light by a respective waveguide of the plurality ofwaveguides 820 that is coupled to the respective light emitting elementof the second plurality of light emitting elements 830, and transmittingthe second light provided by the respective light emitting element ofthe second plurality of light emitting elements 830 via (e.g., by) therespective waveguide 820 as at least a portion of the illumination light490.

In some embodiments, the respective waveguide of the plurality ofwaveguides 820 is tapered, illustrated in FIG. 8C.

In some embodiments, the light source 800 includes a plurality of lightemitting elements (e.g., light emitting elements 810-1 through 810-n,light emitting elements 830, and/or light emitting elements 840). Themethod 1200 further includes (operation 1216) activating a subset, lessthan all, of the plurality of light emitting elements.

In some embodiments, the reflective surface 730-1 is curved.

In some embodiments, the reflective surface 730-1 includes a fullreflector (e.g., a mirror).

In some embodiments, the optical element 730 includes a second surface730-2 that is opposite to the reflective surface 730-1. The method 1200further includes (operation 1232) transmitting the at least a portion490-1 of the illumination light 490 from the light source 410 throughthe second surface 730-2 toward the reflective surface 730-1 andtransmitting the at least a portion 490-1 of the illumination light 490reflected from the reflective surface 730-1 through the second surface730-2.

In some embodiments, the method 1200 further includes (operation 1242)receiving, at a beam splitter 440, the at least a portion 490-1 of theillumination light 490 reflected at the reflective surface 730-1;providing, with the beam splitter 440 the at least a portion 490-1 ofthe illumination light 490 in a first direction toward the spatial lightmodulator 420; modulating the at least a portion 490-1 of theillumination light 490 with the spatial light modulator 420; outputting,from the spatial light modulator 420, the at least a portion 490-1 ofthe illumination light 490 as modulated light; receiving, at the beamsplitter 440, the modulated light output from the spatial lightmodulator 420; and providing, with the beam splitter 440, the modulatedlight in a second direction that is non-parallel to the first direction.

In some embodiments, modulating the at least a portion 490-1 of theillumination light 490 with the spatial light modulator 420 includes(operation 1244) reflecting a subset, less than all, of the at least aportion 490-1 of the illumination light 490.

In light of these principles, we now turn to certain embodiments ofdisplay devices.

In accordance with some embodiments, a display device (e.g., displaydevice 400 shown in FIG. 4A or display device 500 shown in FIG. 5A)includes a light source (e.g., light source 410), a spatial lightmodulator (e.g., spatial light modulator 420), and an optical assembly(e.g., optical assembly 430 or 530). The light source is configured toprovide illumination light and the spatial light modulator is positionedto receive the illumination light. The optical assembly includes a firstreflective surface (e.g., first reflective surface 430-1 or 530-1) and asecond reflective surface (e.g., second reflective surface 430-2 or530-2) that is opposite to the first reflective surface. The opticalassembly is positioned relative to the light source so that at least afirst portion of the illumination light received by the optical assembly(i) is transmitted through the first reflective surface toward thesecond reflective surface, (ii) is reflected by the second reflectivesurface toward the first reflective surface, (iii) is reflected by thefirst reflective surface toward the second reflective surface, and (iv)is transmitted through the second reflective surface.

In some embodiments, the display device (e.g., display device 400 or500) further includes a beam splitter (e.g., PBS 440) that is disposedrelative to (e.g., between) the optical assembly (e.g., optical assembly430 or 530) and the spatial light modulator (e.g., spatial lightmodulator 420) so that the beam splitter receives the at least a firstportion (e.g., first portion 490-1) of the illumination light (e.g.,illumination light 490) that is transmitted through the optical assemblyand provides the at least a first portion of the illumination light in afirst direction. The spatial light modulator modulates the at least afirst portion of the illumination light and outputs modulated light. Thebeam splitter receives the modulated light output from the spatial lightmodulator and provides the modulated light in a second direction that isnon-parallel to the first direction (e.g., the second direction isperpendicular to the first direction).

In some embodiments, the first reflective surface (e.g., firstreflective surface 430-1 or 530-1) is a partial reflector (e.g., 50/50mirror or a mirror having less than 90%, 80%, 70%, 60%, 50%, 40%, 30%,20%, or 10% reflectance).

In some embodiments, at least one of the first reflective surface (e.g.,first reflective surface 430-1 or 530-1) and the second reflectivesurface (e.g., second reflective surface 430-2 or 530-2) is curved. Forexample, in FIG. 4A, the first reflective surface 430-1 is curved. InFIG. 5A, the second reflective surface 530-2 is curved.

In some embodiments, the optical assembly (e.g., optical assembly 530)further includes a third reflective surface (e.g., third reflectivesurface 530-3). The first reflective surface (e.g., first reflectivesurface 530-1) is disposed between the second reflective surface (e.g.,second reflective surface 530-2) and the third reflective surface sothat the optical assembly transmits the at least a first portion (e.g.,first portion 490-1) of the illumination light (e.g., illumination light490) through the third reflective surface toward the first reflectivesurface and receives a second portion (e.g., second portion 490-2) ofthe illumination light, distinct from the at least a first portion ofthe illumination light, such that the second portion of the illuminationlight is: (i) transmitted through the third reflective surface towardthe first reflective surface, (ii) reflected by the first reflectivesurface toward the third reflective surface, (iii) reflected by thethird reflective surface toward the first reflective surface, and (iv)transmitted through the first reflective surface and the secondreflective surface.

In some embodiments, the light source (e.g., light source 800 shown inFIG. 8A, which corresponds to light source 410) includes a plurality oflight emitting elements (e.g., light emitting elements 810) and arespective light emitting element of the plurality of light emittingelements is individually activatable.

In some embodiments, the light (e.g., light source 800 corresponding tolight source 410) includes a first plurality of light emitting elements(e.g., light emitting elements 810-1 through 810-n) and a plurality ofwaveguides (e.g., waveguides 820-1 through 820-n). The first pluralityof light emitting elements is configured to emit first light havingwavelengths in a first wavelength range. A respective waveguide of theplurality of waveguides is coupled to a respective light emittingelement of the first plurality of light emitting elements and isconfigured to transmit the first light emitted from the respective lightemitting element of the first plurality of light emitting elements as atleast a portion of the illumination light (e.g., illumination light490).

In some embodiments, the light source (e.g., light source 800corresponding to light source 410) also includes a second plurality oflight emitting elements (e.g., light emitting elements 830-1 shown inFIG. 8B). The second plurality of light emitting elements is configuredto output second light having wavelengths in a second wavelength rangethat is distinct from the first wavelength range. The respectivewaveguide (e.g., waveguide 820) is further coupled to a respective lightemitting element of the second plurality of light emitting elements andconfigured to transmit the second light emitted from the respectivelight emitting element of the second plurality of light emittingelements as at least a portion of the illumination light (e.g.,illumination light 490).

In some embodiments, a respective waveguide of the plurality ofwaveguides (e.g., waveguide 820-1 through 820-n) is tapered (e.g., FIG.8C).

In some embodiments, the spatial light modulator (e.g., spatial lightmodulator 420) is a reflective spatial light modulator, such as a liquidcrystal on silicon (LCoS) display.

In accordance with some embodiments, a method (e.g., method 900)includes (operation 902) outputting illumination light (e.g.,illumination light 490) from a light source (e.g., light source 410) and(operation 920) receiving the illumination light at a first reflectivesurface (e.g., first reflective surface 430-1 or 530-1) of an opticalassembly (e.g., optical assembly 430 or 530). The optical assembly has asecond reflective surface (e.g., second reflective surface 430-2 or530-2) that is located opposite to the first reflective surface. Themethod also includes (operation 922) transmitting a first portion (e.g.,first portion 490-1) of the illumination light through the firstreflective surface toward the second reflective surface; (operation 924)reflecting, at the second reflective surface, the first portion of theillumination light transmitted through the first reflective surfacetoward the first reflective surface; (operation 926) reflecting, at thefirst reflective surface, the first portion of the illumination lightreflected by the second reflective surface toward the second reflectivesurface; (operation 928) transmitting, through the second reflectivesurface, the first portion of the illumination light reflected by thefirst reflective surface; and (operation 930) receiving the firstportion of the illumination light at a spatial light modulator (e.g.,spatial light modulator 420).

In some embodiments, the light source (e.g., light source 800corresponding to light source 410) includes a first plurality of lightemitting elements (e.g., light emitting elements 810-1 through 810-n)and a plurality of waveguides (e.g., waveguide 820-1 through 820-n). Themethod (e.g., method 900) further includes (operation 904) providing,from a respective light emitting element of the first plurality of lightemitting elements, first light having wavelengths in a first wavelengthrange; guiding the first light by a respective waveguide of theplurality of waveguides that is coupled to the respective light emittingelement of the first plurality of light emitting elements; andtransmitting, by the respective waveguide, the first light provided bythe respective light emitting element of the first plurality of lightemitting elements as at least a portion of the illumination light (e.g.,illumination light 490).

In some embodiments, the light source (e.g., light source 800corresponding to light source 410) also includes a second plurality oflight emitting elements (e.g., light emitting elements 830). The method(e.g., method 900) further includes (operation 910) providing, from arespective light emitting element of the second plurality of lightemitting elements, second light having wavelengths in a secondwavelength range distinct from the first wavelength range; guiding thesecond light by a respective waveguide of the plurality of waveguides(e.g., waveguides 820-1 through 820-n) that is coupled to the respectivelight emitting element of the second plurality of light emittingelements; and transmitting, by the respective waveguide, the secondlight provided by the respective light emitting element of the secondplurality of light emitting elements as at least a portion of theillumination light (e.g., illumination light 490).

In some embodiments, the respective waveguide of the plurality ofwaveguides (e.g., waveguides 820-1 through 820-n) is tapered.

In some embodiments, the light source (e.g., light source 800corresponding to light source 410) includes a plurality of lightemitting elements (e.g., light emitting elements 810-1 through 810-n)and the method (e.g., method 900) includes (operation 916) activating asubset, less than all, of the plurality of light emitting elements.

In some embodiments, the optical assembly (e.g., optical assembly 530)further includes a third reflective surface (e.g., third reflectivesurface 530-3). The method (e.g., method 900) further includes(operation 940) transmitting, through the third reflective surface, thefirst portion (e.g., first portion 490-1) of the illumination light(e.g., illumination light 490) and a second portion (e.g., secondportion 490-2) of the illumination light toward the first reflectivesurface. The second portion of the illumination light is distinct fromthe first portion of the illumination light. The method also includesreflecting the second portion of the illumination light at the firstreflective surface (e.g., first reflective surface 530-1) toward thethird reflective surface; reflecting, at the third reflective surface,the second portion of the illumination light reflected at the firstreflective surface toward the third reflective surface; transmitting,through the first reflective surface and the second reflective surface,the second portion of the illumination light reflected by the thirdreflective surface; and receiving the second portion of the illuminationlight at the spatial light modulator (e.g., spatial light modulator420).

In some embodiments, the method (e.g., method 900) further includes(operation 950) receiving, at a beam splitter (e.g., PBS 440), the firstportion (e.g., first portion 490-1) of the illumination light (e.g.,illumination light 490) transmitted through the second reflectivesurface (e.g., second reflective surface 430-2 or 530-2; providing, withthe beam splitter, the first portion of the illumination light in afirst direction toward the spatial light modulator (e.g., illuminationlight 390 shown in FIG. 3B); modulating, with the spatial lightmodulator, the first portion of the illumination light; outputtingmodulated light from the spatial light modulator; receiving, at the beamsplitter, the modulated light output from the spatial light modulator;and providing, with the beam splitter, the modulated light in a seconddirection that is non-parallel to the first direction (e.g., modulatedlight 392).

In some embodiments, modulating the first portion of the illuminationlight with the spatial light modulator includes (operation 952)reflecting a subset, less than all, of the first portion of theillumination light.

In some embodiments, the first reflective surface (e.g., firstreflective surface 430-1 or 530-1) is a partial reflector.

In some embodiments, at least one of the first reflective surface (e.g.,first reflective surface 430-1 or 530-1) and the second reflectivesurface (e.g., second reflective surface 430-2 or 530-2) is curved.

In accordance with some embodiments, a display device (e.g., displaydevice 402 shown in FIG. 4G or display device 502 shown in FIG. 5C)includes a light source (e.g., light source 410), a spatial lightmodulator (e.g., spatial light modulator 420), or an optical assembly(e.g., optical assembly 432 or 532). The light source is configured toprovide illumination light (e.g., illumination light 490) and thespatial light modulator is positioned to receive the illumination light.The optical assembly includes a first reflective surface (e.g., firstreflective surface 432-1 or 532-1) that defines an aperture (e.g.,aperture 434 or 534) and a second reflective surface (e.g., secondreflective surface 432-2 or 532-2) that is opposite to the firstreflective surface. The optical assembly is positioned relative to thelight source so that at least a first portion of the illumination lightreceived by the optical assembly is (i) reflected by the secondreflective surface toward the first reflective surface, (ii) reflectedby the first reflective surface toward the second reflective surface,and (iii) transmitted through the second reflective surface.

In some embodiments, a beam splitter (e.g., PBS 440) is disposedrelative to the optical assembly (e.g., optical assembly 432 or 532) andthe spatial light modulator (e.g., spatial light modulator 420) so thatthe beam splitter receives the at least a first portion (e.g., firstportion 490-1) of the illumination light (e.g., illumination light 490)output from the optical assembly and directs the at least a firstportion of the illumination light in a first direction. The spatiallight modulator modulates the at least a first portion of theillumination light and outputs modulated light. The beam splitterreceives the modulated light output from the spatial light modulator anddirects the modulated light in a second direction that is non-parallelto the first direction.

In some embodiments, the light source (e.g., light source 410) islocated outside a space between the first reflective surface (e.g.,first reflective surface 430-1 or 530-1) and the second reflectivesurface (e.g., second reflective surface 430-2 or 530-2). For example,the first reflective surface is located between the light source and thesecond reflective surface. The light source is aligned with the aperture(e.g., aperture 434 or 534) in the first reflective surface so that theillumination light (e.g., illumination light 490), including the atleast a first portion (e.g., first portion 490-1) of the illuminationlight, is transmitted through the aperture of the first reflectivesurface toward the second reflective surface before being reflected bythe second reflective surface.

In some embodiments, at least a portion of the light source (e.g., lightsource 410) is disposed inside the aperture (e.g., aperture 434 or 534)defined by the first reflective surface (e.g., first reflective surface430-1 or 530-1). For example, a portion of the light source remainsinserted into the aperture.

In some embodiments, the optical assembly (e.g., optical assembly 532)further includes a third reflective surface (e.g., third reflectivesurface 532-3) and the second reflective surface (e.g., secondreflective surface 532-2) is disposed between the first reflectivesurface (e.g., first reflective surface 532-1) and the third reflectivesurface so that a second portion (e.g., second portion 490-2) of theillumination light (e.g., illumination light 490) received by theoptical assembly is: (i) transmitted through the second reflectivesurface toward the third reflective surface, (ii) reflected by the thirdreflective surface toward the second reflective surface, (iii) reflectedby the second reflective surface toward the third reflective surface,and (iv) transmitted through the third reflective surface.

In some embodiments, the light source (e.g., light source 410) includesa plurality of light emitting elements (e.g., light emitting elements810 shown in FIG. 8A). A respective light emitting element of theplurality of light emitting elements is individually activatable.

In some embodiments, the light source (e.g., light source 410) includesa first plurality of light emitting elements (e.g., light emittingelements 810-1 through 810-n) and a plurality of waveguides (e.g.,waveguides 820-1 through 820-n shown in FIG. 8A). A respective lightemitting element of the first plurality of light emitting elements isconfigured to emit first light having wavelengths in a first wavelengthrange. A respective waveguide of the plurality of waveguides is coupledto the respective light emitting element of the first plurality of lightemitting elements and configured to transmit the first light emittedfrom the respective light emitting element of the first plurality oflight emitting elements as at least a portion of the illumination light(e.g., illumination light 490).

In some embodiments, the light source (e.g., light source) also includesa second plurality of light emitting elements (e.g., light emittingelements 830-1 through 830-n shown in FIG. 8B). A respective lightemitting element of the second plurality of light emitting elements isconfigured to output second light having wavelengths in a secondwavelength range that is distinct from the first wavelength range. Therespective waveguide (e.g., waveguide 820) is further coupled to arespective light emitting element of the second plurality of lightemitting elements and configured to transmit the second light emittedfrom the respective light emitting element of the second plurality oflight emitting elements as at least a portion of the illumination light(e.g., illumination light 490).

In some embodiments, a respective waveguide of the plurality ofwaveguides (e.g., waveguide 820-1 through 820-n shown in FIG. 8C) istapered.

In some embodiments, the spatial light modulator (e.g., spatial lightmodulator 420) is a reflective spatial light modulator.

In accordance with some embodiments, a method (e.g., method 1000)includes (operation 1002) outputting illumination light (e.g.,illumination light 490) from a light source (e.g., light source 410).The light source is positioned adjacent to a first reflective surface(e.g., first reflective surface 432-1 or reflective surface 532-3) of anoptical assembly (e.g., optical assembly 432 or 532). The firstreflective surface defines an aperture (e.g., aperture 434 or 534). Theoptical assembly includes a second reflective surface (e.g., secondreflective surface 432-2 or first reflective surface 532-1) that islocated opposite to the first reflective surface. The method includes(operation 1030) reflecting, at the second reflective surface, a firstportion (e.g., first portion 490-1) of the illumination light toward thefirst reflective surface; (operation 1032) reflecting, at the firstreflective surface, the first portion of the illumination lightreflected by the second reflective surface toward the second reflectivesurface; (operation 1034) transmitting, through the second reflectivesurface, the first portion of the illumination light reflected by thefirst reflective surface; and (operation 1036) receiving the firstportion of the illumination light at a spatial light modulator (e.g.,spatial light modulator 420).

In some embodiments, the light source (e.g., light source 800corresponding to light source 410) includes a first plurality of lightemitting elements (e.g., light emitting elements 810-1 through 810-n)and a plurality of waveguides (e.g., waveguides 820-1 through 820-n).The method (e.g., method 1000) further includes (operation 1006)providing, from a respective light emitting element of the firstplurality of light emitting elements, first light having wavelengths ina first wavelength range; guiding the first light by a respectivewaveguide of the plurality of waveguides that is coupled to therespective light emitting element of the first plurality of lightemitting elements; and transmitting, by the respective waveguide, thefirst light provided by the respective light emitting element of thefirst plurality of light emitting elements as at least a portion of theillumination light (e.g., illumination light 490).

In some embodiments, the light source (e.g., light source 800corresponding to light source 410) also includes a second plurality oflight emitting elements (e.g., light emitting elements 830). The method(e.g., method 1000) further includes (operation 1010) providing, from arespective light emitting element of the second plurality of lightemitting elements, second light having wavelengths in a secondwavelength range distinct from the first wavelength range; guiding thesecond light by a respective waveguide of the plurality of waveguides(e.g., waveguides 820-1 through 820-n) that is coupled to the respectivelight emitting element of the second plurality of light emittingelements; and transmitting, by the respective waveguide, the secondlight provided by the respective light emitting element of the secondplurality of light emitting elements as at least a portion of theillumination light (e.g., illumination light 490).

In some embodiments, the respective waveguide of the plurality ofwaveguides (e.g., waveguides 820-1 through 820-n) is tapered.

In some embodiments, the light source (e.g., light source 800corresponding to light source 410) includes a plurality of lightemitting elements (e.g., light emitting elements 810-1 through 810-n).The method (e.g., method 1000) includes (operation 1014) activating asubset, less than all, of the plurality of light emitting elements.

In some embodiments, the method (e.g., method 1000) further includes(operation 1020) transmitting the illumination light (e.g., illuminationlight 490), including the first portion (e.g., first portion 490-1) ofthe illumination light, through the aperture (e.g., aperture 434 or 534)in the first reflective surface (e.g., first reflective surface 432-1 orreflective surface 532-3) toward the second reflective surface (e.g.,second reflective surface 432-2 or reflective surface 532-1).

In some embodiments, at least a portion of the light source (e.g., lightsource 410) is disposed in the aperture (e.g., aperture 434 or 534) inthe first reflective surface (e.g., first reflective surface 432-1 orthird reflective surface 532-3).

In some embodiments, the optical assembly (e.g., optical assembly 532)further includes a third reflective surface (e.g., second reflectivesurface 532-2) and the method (e.g., method 1000) further includes(operation 1040) transmitting a second portion (e.g., second portion490-2) of the illumination light (e.g., illumination light 490) at thesecond reflective surface (e.g., first reflective surface 532-1) towardthe third reflective surface. The second portion of the illuminationlight is distinct from the first portion (e.g., first portion 490-1) ofthe illumination light. The method also includes reflecting, at thethird reflective surface, the second portion of the illumination lighttransmitted at the second reflective surface toward the secondreflective surface; reflecting, at the second reflective surface, thesecond portion of the illumination light reflected at the thirdreflective surface toward the third reflective surface; andtransmitting, through the third reflective surface, the second portionof the illumination light reflected by the second reflective surface.

In some embodiments, the method (e.g., method 1000) further includes(operation 1050) receiving, at a beam splitter (e.g., PBS 440), thefirst portion (e.g., first portion 490-1) of the illumination light(e.g., illumination light 490) transmitted through the second reflectivesurface (e.g., second reflective surface 432-2 or first reflectivesurface 532-1); directing, with the beam splitter, the first portion ofthe illumination light in a first direction toward the spatial lightmodulator (e.g., spatial light modulator 420); modulating, with thespatial light modulator, the first portion of the illumination light;outputting modulated light from the spatial light modulator; receiving,at the beam splitter, the modulated light output from the spatial lightmodulator; and directing, with the beam splitter, the modulated light ina second direction that is non-parallel to the first direction.

In some embodiments, modulating the first portion (e.g., first portion490-1) of the illumination light (e.g., illumination light 490) with thespatial light modulator (e.g., spatial light modulator 420) includes(operation 1052) reflecting a subset, less than all, of the firstportion of the illumination light.

In accordance with some embodiments, a display device (e.g., displaydevice 600 shown in FIG. 6A, display device 602 shown in FIG. 6D, ordisplay device 604 shown in FIG. 6E) includes a light source (e.g.,light source 410), a spatial light modulator (e.g., spatial lightmodulator 420), and an optical assembly (e.g., optical assembly 630,632, 634). The light source is configured to provide illumination light(e.g., illumination light 490) and the spatial light modulator ispositioned to receive the illumination light. The optical assemblyincludes an optical element (e.g., optical element 640) and a curvedreflector (e.g., curved reflector 650) that is distinct and separatefrom the optical element. The curved reflector is disposed relative tothe light source so that at least a portion (e.g., portion 490-1) of theillumination light is: (i) reflected by the curved reflector toward theoptical element, (ii) reflected by the optical element toward the curvedreflector, and (iii) transmitted through the curved reflector.

In some embodiments, the display device (e.g., display device 600, 602,or 604) includes a beam splitter (e.g., PBS 440) disposed relative tothe optical assembly (e.g., optical assembly 630, 632, 634) and thespatial light modulator (e.g., spatial light modulator 420) so that thebeam splitter receives the at least a portion (e.g., portion 490-1) ofthe illumination light (e.g., illumination light 490) output from thelight source (e.g., light source 410) and provides the at least aportion of the illumination light in a first direction. The spatiallight modulator (e.g., spatial light modulator 420) modulates theillumination light and outputs modulated light. The beam splitterreceives the modulated light output from the spatial light modulator andprovides the modulated light in a second direction that is non-parallelto the first direction.

In some embodiments, the optical assembly is disposed relative to thelight source and the spatial light modulator so that the at least aportion of the illumination light received by the optical assembly istransmitted through the optical element toward the curved reflectorbefore being reflected by the curved reflector.

In some embodiments, the optical element (e.g., optical element 640)defines an aperture (e.g., aperture 644) and the optical assembly isdisposed relative to the light source (e.g., light source 410) and thespatial light modulator (e.g., spatial light modulator 420) so that theat least a portion (e.g., portion 490-1) of the illumination light(e.g., illumination light 490) received by the optical assembly (e.g.,optical assembly 630, 632, or 634) is transmitted through the apertureof the optical element toward the curved reflector (e.g., curvedreflector 650) before being reflected by the curved reflector.

In some embodiments, at least a portion of the light source (e.g., lightsource 410) is disposed inside the aperture (e.g., aperture 644) of theoptical element (e.g., optical element 640).

In some embodiments, the light source (e.g., light source 410) isdisposed between the curved reflector (e.g., curved reflector 650) andthe optical element (e.g., optical element 640).

In some embodiments, the optical element (e.g., optical element 640) isa partial reflector (e.g., a 50/50 mirror).

In some embodiments, the light source (e.g., light source 800 shown inFIG. 8A, corresponding to light source 410) includes a plurality oflight emitting elements (e.g., light emitting elements 810-1 to 810-n).A respective light emitting element of the plurality of light emittingelements is individually activatable.

In some embodiments, the light source (e.g., light source 800corresponding to light source 410) includes a first plurality of lightemitting elements (e.g., light emitting elements 810-1 to 810-n) and aplurality of waveguides (e.g., waveguides 820-1 through 820-n). Arespective light emitting element of the first plurality of lightemitting elements is configured to emit first light having wavelengthsin a first wavelength range. A respective waveguide of the plurality ofwaveguides is coupled to a respective light emitting element of thefirst plurality of light emitting elements and is configured to transmitthe first light emitted from the respective light emitting element ofthe first plurality of light emitting elements as at least a portion ofthe illumination light (e.g., illumination light 490).

In some embodiments, the light source (e.g., light source 800corresponding to light source 410) also includes a second plurality oflight emitting elements (e.g., light emitting elements 830 shown in FIG.8B). The second plurality of light emitting elements is configured tooutput second light having wavelengths in a second wavelength range thatis distinct from the first wavelength range. The respective waveguide(e.g., waveguide 820) is further coupled to a respective light emittingelement of the second plurality of light emitting elements and isconfigured to transmit the second light emitted from the respectivelight emitting element of the second plurality of light emittingelements as at least a portion of the illumination light (e.g.,illumination light 490).

In some embodiments, a respective waveguide of the plurality ofwaveguides (e.g., waveguides 820-1 through 820-n shown in FIG. 8C) istapered.

In accordance with some embodiments, a method (e.g., method 1100)includes (operation 1102) outputting illumination light (e.g.,illumination light 490) from a light source (e.g., light source 410),(operation 1130) receiving the illumination light at a curved reflector(e.g., curved reflector 650), and (operation 1132) reflecting at least aportion (e.g., portion 490-1) of the illumination light (e.g.,illumination light 490) at the curved reflector (e.g., curved reflector650). The method also includes (operation 1134) reflecting, at anoptical element (e.g., optical element 640), the at least a portion ofthe illumination light reflected by the curved reflector toward thecurved reflector; (operation 1136) transmitting, through the curvedreflector, the at least a portion of the illumination light reflected bythe optical element; and (operation 1138) receiving the at least aportion of the illumination light at a spatial light modulator (e.g.,spatial light modulator 420).

In some embodiments, the light source (e.g., light source 410) isdisposed between the curved reflector (e.g., curved reflector 650) andthe optical element (e.g., optical element 640).

In some embodiments, the optical element (e.g., optical element 640) isa partial reflector (e.g., a 50/50 mirror).

In some embodiments, the light source (e.g., light source 800corresponding to light source 410) includes a first plurality of lightemitting elements (e.g., light emitting elements 810-1 through 810-n)and a plurality of waveguides (e.g., waveguides 820-1 through 820-n).The method (e.g., method 1100) further includes (operation 1104)providing, from a respective light emitting element of the firstplurality of light emitting elements, first light having wavelengths ina first wavelength range; guiding the first light by a respectivewaveguide of the plurality of waveguides that is coupled to therespective light emitting element of the first plurality of lightemitting elements; and transmitting, by the respective waveguide, thefirst light provided by the respective light emitting element of thefirst plurality of light emitting elements as at least a portion of theillumination light (e.g., illumination light 490).

In some embodiments, the light source (e.g., light source 800corresponding to light source 410) also includes a second plurality oflight emitting elements (e.g., light emitting elements 830). The method(e.g., method 1100) further includes (operation 1112) providing, from arespective light emitting element of the second plurality of lightemitting elements, second light having wavelengths in a secondwavelength range distinct from the first wavelength range; guiding thesecond light by a respective waveguide of the plurality of waveguides(e.g., waveguides 820-1 through 820-n) that is coupled to the respectivelight emitting element of the second plurality of light emittingelements; and transmitting, by the respective waveguide, the secondlight provided by the respective light emitting element of the secondplurality of light emitting elements as at least a portion of theillumination light (e.g., illumination light 490).

In some embodiments, the respective waveguide of the plurality ofwaveguides (e.g., waveguides 820-1 through 820-n) is tapered.

In some embodiments, the light source (e.g., light source 800corresponding to light source 410) includes a plurality of lightemitting elements (e.g., light emitting elements 810-1 through 810-n).The method (e.g., method 1100) also includes (operation 1122) activatinga subset, less than all, of the plurality of light emitting elements.

In some embodiments, the optical element (e.g., optical element 640) isdisposed relative the light source (e.g., light source 410) and thecurved reflector (e.g., curved reflector 650). The method (e.g., method1100) further including (operation 1124) transmitting the at least aportion (e.g., portion 490-1) of the illumination light (e.g.,illumination light 490) through the optical element (e.g., opticalelement 640) toward the curved reflector (e.g., curved reflector 650).

In some embodiments, the optical element (e.g., optical element 640)defines an aperture (e.g., aperture 644). The method (e.g., method 1100)further includes (operation 1126) transmitting the at least a (e.g.,portion 490-1) of the illumination light (e.g., illumination light 490)through the aperture of the optical element toward the curved reflector(e.g., curved reflector 650).

In some embodiments, the optical element (e.g., optical element 640)defines an aperture (e.g., aperture 644) and at least a portion of thelight source (e.g., light source 410) is disposed inside the aperture ofthe optical element.

In some embodiments, the method (e.g., method 1100) further includes(operation 1140) receiving, at a beam splitter (e.g., PBS 440), the atleast a portion (e.g., portion 490-1) of the illumination light (e.g.,illumination light 490) transmitted through the curved reflector (e.g.,curved reflector 650); providing, with the beam splitter, the at least aportion of the illumination light in a first direction toward thespatial light modulator (e.g., spatial light modulator 420); modulating,with the spatial light modulator, the at least a portion of theillumination light; outputting, from the spatial light modulator, the atleast a portion of the illumination light as modulated light; receivingthe modulated light output from the spatial light modulator at the beamsplitter; and providing, with the beam splitter, the modulated light ina second direction that is non-parallel to the first direction.

In some embodiments, modulating the at least a portion of theillumination light with the spatial light modulator includes (operation1146) reflecting a subset, less than all, of the at least a portion ofthe illumination light (e.g., illumination light 490).

In accordance with some embodiments, a display device (e.g., displaydevice 700 shown in FIG. 7 includes a light source (e.g., light source410), a spatial light modulator (e.g., spatial light modulator 420), andan optical element (e.g., optical element 730). The light source isconfigured to provide illumination light (e.g., illumination light 490)and the spatial light modulator is positioned to receive theillumination light. The optical element includes a reflective surface(e.g., reflective surface 730-1). The optical element is positionedrelative to the light source so that at least a portion (e.g., portion490-1) of the illumination light (e.g., illumination light 490) receivedby the optical element is reflected at the reflective surface backtoward the light source.

In some embodiments, the display device (e.g., display device 700)includes a beam splitter (e.g., PBS 440) that is disposed relative tothe optical element (e.g., optical element 730) and the spatial lightmodulator (e.g., spatial light modulator 420) so that the beam splitterreceives at least a portion (e.g., portion 490-1) of the illuminationlight (e.g., illumination light 490) reflected at the reflective surface(e.g., reflective surface 730-1) and provides the at least a portion(e.g., portion 490-1) of the illumination light (e.g., illuminationlight 490) in a first direction. The spatial light modulator modulatesthe at least a portion of the illumination light and outputs modulatedlight. The beam splitter receives the modulated light output from thespatial light modulator and provides the modulated light in a seconddirection that is non-parallel to the first direction.

In some embodiments, the reflective surface (e.g., reflective surface730-1) is curved.

In some embodiments, the optical element (e.g., optical element 730)includes a second surface (e.g., second surface 730-2) that is oppositeto the reflective surface (e.g., reflective surface 730-1). Thereflective surface has a first radius of curvature and the secondsurface has a second radius of curvature that is different from thefirst curvature.

In some embodiments, the reflective surface (e.g., reflective surface730-1) includes a full reflector (e.g., a mirror).

In some embodiments, the light source (e.g., light source 800 shown inFIG. 8A, corresponding to light source 410) includes a plurality oflight emitting elements (e.g., light emitting elements 810-1 to 810-n).A respective light emitting element of the plurality of light emittingelements is individually activatable.

In some embodiments, the light source (e.g., light source 800corresponding to light source 410) includes a first plurality of lightemitting elements (e.g., light emitting elements 810-1 to 810-n) and aplurality of waveguides (e.g., waveguides 820-1 through 820-n). Arespective light emitting element of the first plurality of lightemitting elements is configured to emit first light having wavelengthsin a first wavelength range. A respective waveguide of the plurality ofwaveguides is coupled to a respective light emitting element of thefirst plurality of light emitting elements and is configured to transmitthe first light emitted from the respective light emitting element ofthe first plurality of light emitting elements as at least a portion ofthe illumination light (e.g., illumination light 490).

In some embodiments, the light source (e.g., light source 800corresponding to light source 410) also includes a second plurality oflight emitting elements (e.g., light emitting elements 830 shown in FIG.8B). The second plurality of light emitting elements is configured tooutput second light having wavelengths in a second wavelength range thatis distinct from the first wavelength range. The respective waveguide(e.g., waveguide 820) is further coupled to a respective light emittingelement of the second plurality of light emitting elements and isconfigured to transmit the second light emitted from the respectivelight emitting element of the second plurality of light emittingelements as at least a portion of the illumination light (e.g.,illumination light 490).

In some embodiments, a respective waveguide of the plurality ofwaveguides (e.g., waveguides 820-1 through 820-n shown in FIG. 8C) istapered.

In some embodiments, the spatial light modulator (e.g., spatial lightmodulator 420) is a reflective spatial light modulator.

In accordance with some embodiments, a method (e.g., method 1200)includes (operation 1202) outputting illumination light (e.g.,illumination light 490) from a light source (e.g., light source 410),(operation 1220) receiving at least a portion (e.g., portion 490-1) ofthe illumination light at a reflective surface (e.g., reflective surface730-1) of an optical element (e.g., optical element 730), (operation1230) reflecting the at least a portion of the illumination light at thereflective surface, and (operation 1240) receiving the at least aportion of the illumination light at a spatial light modulator (e.g.,spatial light modulator 420).

In some embodiments, the reflective surface (e.g., reflective surface730-1) is curved.

In some embodiments, the reflective surface (e.g., reflective surface730-1) includes a full reflector (e.g., mirror).

In some embodiments, the light source (e.g., light source 800corresponding to light source 410) includes a first plurality of lightemitting elements (e.g., light emitting elements 810-1 through 810-n)and a plurality of waveguides (e.g., waveguides 820-1 through 820-n).The method (e.g., method 1200) further includes (operation 1210)providing, from a respective light emitting element of the firstplurality of light emitting elements, first light having wavelengths ina first wavelength range; guiding the first light by a respectivewaveguide of the plurality of waveguides that is coupled to therespective light emitting element of the first plurality of lightemitting elements; and transmitting, by the respective waveguide, thefirst light provided by the respective light emitting element of thefirst plurality of light emitting elements as at least a portion of theillumination light (e.g., illumination light 490).

In some embodiments, the light source (e.g., light source 800corresponding to light source 410) also includes a second plurality oflight emitting elements (e.g., light emitting elements 830). The method(e.g., method 1200) further includes (operation 1212) providing, from arespective light emitting element of the second plurality of lightemitting elements, second light having wavelengths in a secondwavelength range distinct from the first wavelength range; guiding thesecond light by a respective waveguide of the plurality of waveguides(e.g., waveguides 820-1 through 820-n) that is coupled to the respectivelight emitting element of the second plurality of light emittingelements; and transmitting, by the respective waveguide, the secondlight provided by the respective light emitting element of the secondplurality of light emitting elements as at least a portion of theillumination light (e.g., illumination light 490).

In some embodiments, the respective waveguide of the plurality ofwaveguides (e.g., waveguides 820-1 through 820-n) is tapered.

In some embodiments, the light source (e.g., light source 800corresponding to light source 410) includes a plurality of lightemitting elements (e.g., light emitting elements 810-1 through 810-n).The method (e.g., method 1200) also includes (operation 1216) activatinga subset, less than all, of the plurality of light emitting elements.

In some embodiments, the optical element (e.g., optical element 730)includes a second surface (e.g., second surface 730-2) that is oppositeto the reflective surface (e.g., reflective surface 730-1). The method(e.g., method 1200) further includes (operation 1232) transmitting theat least a portion (e.g., portion 490-1) of the illumination light(e.g., illumination light 490) from the light source (e.g., light source410) through the second surface toward the reflective surface, andtransmitting the at least a portion of the illumination light reflectedfrom the reflective surface through the second surface.

In some embodiments, the method (e.g., method 1200) further includes(operation 1242) receiving, at a beam splitter (e.g., PBS 440), the atleast a portion (e.g., portion 490-1) of illumination light (e.g.,illumination light 490) reflected at the reflective surface (e.g.,reflective surface 730-1); providing, with the beam splitter, the atleast a portion of the illumination light in a first direction towardthe spatial light modulator (spatial light modulator 420); modulatingthe at least a portion of the illumination light with the spatial lightmodulator; outputting, from the spatial light modulator, the at least aportion of the illumination light as modulated light; receiving, at thebeam splitter, the modulated light output from the spatial lightmodulator; and providing, with the beam splitter, the modulated light ina second direction that is non-parallel to the first direction.

In some embodiments, modulating the at least a portion (e.g., portion490-1) of the illumination light (e.g., illumination light 490) with thespatial light modulator (e.g., spatial light modulator 420) includes(operation 1244) reflecting a subset, less than all, of the at least aportion of the illumination light.

Although various drawings illustrate operations of particular componentsor particular groups of components with respect to one eye, a personhaving ordinary skill in the art would understand that analogousoperations can be performed with respect to the other eye or both eyes.For brevity, such details are not repeated herein.

Although some of various drawings illustrate a number of logical stagesin a particular order, stages which are not order dependent may bereordered and other stages may be combined or broken out. While somereordering or other groupings are specifically mentioned, others will beapparent to those of ordinary skill in the art, so the ordering andgroupings presented herein are not an exhaustive list of alternatives.Moreover, it should be recognized that the stages could be implementedin hardware, firmware, software or any combination thereof.

The foregoing description, for purpose of explanation, has beendescribed with reference to specific embodiments. However, theillustrative discussions above are not intended to be exhaustive or tolimit the scope of the claims to the precise forms disclosed. Manymodifications and variations are possible in view of the aboveteachings. The embodiments were chosen in order to best explain theprinciples underlying the claims and their practical applications, tothereby enable others skilled in the art to best use the embodimentswith various modifications as are suited to the particular usescontemplated.

What is claimed is:
 1. A display device, comprising: a light sourceconfigured to provide illumination light; a spatial light modulatorpositioned to receive the illumination light; and an optical assemblyincluding an optical element and a curved reflector that is distinct andseparate from the optical element, the curved reflector being disposedrelative to the light source so that at least a portion of theillumination light is reflected by the curved reflector toward theoptical element, is reflected by the optical element toward the curvedreflector, and is transmitted through the curved reflector, wherein theoptical element is a partial reflector and the optical assembly isdisposed relative to the light source and the spatial light modulator sothat the at least a portion of the illumination light received by theoptical assembly is transmitted through the optical element toward thecurved reflector before being reflected by the curved reflector.
 2. Thedisplay device of claim 1, further comprising: a beam splitter disposedrelative to the optical assembly and the spatial light modulator so thatthe beam splitter receives the at least a portion of the illuminationlight output from the light source and provides the at least a portionof the illumination light in a first direction, the spatial lightmodulator modulates the illumination light and outputs modulated light,and the beam splitter receives the modulated light output from thespatial light modulator and provides the modulated light in a seconddirection that is non-parallel to the first direction.
 3. The displaydevice of claim 1, wherein: the optical element defines an aperture; theoptical assembly is disposed relative to the light source and thespatial light modulator so that the at least a portion of theillumination light received by the optical assembly is transmittedthrough the aperture of the optical element toward the curved reflectorbefore being reflected by the curved reflector; and at least a portionof the light source is disposed inside the aperture of the opticalelement.
 4. The display device of claim 1, wherein: the light sourceincludes a plurality of light emitting elements; and a respective lightemitting element of the plurality of light emitting elements isindividually activatable.
 5. The display device of claim 1, wherein thelight source includes: a first plurality of light emitting elementsconfigured to emit first light having wavelengths in a first wavelengthrange; and a plurality of waveguides, a respective waveguide of theplurality of waveguides being coupled to a respective light emittingelement of the first plurality of light emitting elements and configuredto transmit the first light emitted from the respective light emittingelement of the first plurality of light emitting elements as at least aportion of the illumination light.
 6. The display device of claim 5,wherein: the light source also includes a second plurality of lightemitting elements; the second plurality of light emitting elements isconfigured to output second light having wavelengths in a secondwavelength range that is distinct from the first wavelength range; andthe respective waveguide is further coupled to a respective lightemitting element of the second plurality of light emitting elements andconfigured to transmit the second light emitted from the respectivelight emitting element of the second plurality of light emittingelements as at least a portion of the illumination light.
 7. The displaydevice of claim 5, wherein a respective waveguide of the plurality ofwaveguides is tapered.
 8. A display device, comprising: a light sourceconfigured to provide illumination light; a spatial light modulatorpositioned to receive the illumination light; and an optical assemblyincluding an optical element and a curved reflector that is distinct andseparate from the optical element, the curved reflector being disposedrelative to the light source so that at least a portion of theillumination light is reflected by the curved reflector toward theoptical element, is reflected by the optical element toward the curvedreflector, and is transmitted through the curved reflector, wherein thelight source is disposed between the curved reflector and the opticalelement.
 9. A method, comprising: outputting illumination light from alight source; receiving the illumination light at a curved reflector;reflecting, at the curved reflector, at least a portion of theillumination light; reflecting, at an optical element, the at least aportion of the illumination light reflected by the curved reflectortoward the curved reflector; transmitting, through the curved reflector,the at least a portion of the illumination light reflected by theoptical element; and receiving the at least a portion of theillumination light at a spatial light modulator, wherein the opticalelement defines an aperture and at least a portion of the light sourceis disposed inside the aperture of the optical element.
 10. The methodof claim 9, further comprising: receiving, at a beam splitter, the atleast a portion of the illumination light transmitted through the curvedreflector; providing, with the beam splitter, the at least a portion ofthe illumination light in a first direction toward the spatial lightmodulator; modulating, with the spatial light modulator, the at least aportion of the illumination light; outputting, from the spatial lightmodulator, the at least a portion of the illumination light as modulatedlight; receiving, at the beam splitter, the modulated light output fromthe spatial light modulator; and providing, with the beam splitter, themodulated light in a second direction that is non-parallel to the firstdirection.
 11. The method of claim 10, wherein: modulating the at leasta portion of the illumination light with the spatial light modulatorincludes reflecting a subset, less than all, of the at least a portionof the illumination light.
 12. The method of claim 9, wherein: the lightsource includes a plurality of light emitting elements; and the methodalso includes activating a subset, less than all, of the plurality oflight emitting elements.
 13. The method of claim 9, wherein the lightsource includes a first plurality of light emitting elements and aplurality of waveguides, the method further comprising: providing, froma respective light emitting element of the first plurality of lightemitting elements, first light having wavelengths in a first wavelengthrange; guiding the first light by a respective waveguide of theplurality of waveguides that is coupled to the respective light emittingelement of the first plurality of light emitting elements; andtransmitting, by the respective waveguide, the first light provided bythe respective light emitting element of the first plurality of lightemitting elements as at least a portion of the illumination light. 14.The method of claim 13, wherein the light source also includes a secondplurality of light emitting elements, the method further comprising:providing, from a respective light emitting element of the secondplurality of light emitting elements, second light having wavelengths ina second wavelength range distinct from the first wavelength range;guiding the second light by a respective waveguide of the plurality ofwaveguides that is coupled to the respective light emitting element ofthe second plurality of light emitting elements; and transmitting, bythe respective waveguide, the second light provided by the respectivelight emitting element of the second plurality of light emittingelements as at least a portion of the illumination light.
 15. Thedisplay device of claim 1, wherein the partial reflector has apredefined reflectance and a predefined transmittance.
 16. The displaydevice of claim 1, wherein the partial reflector has less than 90%reflectance and at least 15% transmittance.
 17. The display device ofclaim 16, wherein the partial reflector has 50% reflectance and 50%transmittance.